typewriter/docs/quality-house.md

Quality House

The 13 WHATs × 15 HOWs House of Quality. The roof carries function-vs- function correlations; the basement carries v0.1 targets (mirrored from qfd.md §2) plus the weighted-vote sums (Σ = Σ(W weight × cell strength)) and rounded relative weights. The narrative reading of these numbers lives in qfd.md §3 (priority list) and §4 (conflict list).

This file is the authoritative source for the matrix cells, the roof correlations, and the basement Σ + relative weights. WHATs (§1) and HOWs (§2) are mirrored here from qfd.md; if those diverge, trust qfd.md.

Out of scope here: §5 component mapping (would need a second house), §6 critical performance budget (already a curated rank), §7 tradeoffs (narrative), §8 inconsistencies (history).

The perception zone scores four products against the WHATs on a 0–5 scale. These are educated guesses, not measurements — see the scoring rationale below for what each cell is based on. Useful for self-positioning ("where do we land vs the market"), not as a fair head-to-head buyer's guide.

% =====================================================================
% QFD "House of Quality" preamble
% =====================================================================
\usetikzlibrary{arrows.meta, positioning, shapes.geometric, shapes.misc, calc, fit, backgrounds}

\newif\ifqfdshowroof          \qfdshowrooftrue
\newif\ifqfdshowbasement      \qfdshowbasementtrue
\newif\ifqfdshowcompetitive   \qfdshowcompetitivetrue
\newif\ifqfdshowlegend        \qfdshowlegendtrue
\newif\ifqfdshowimportance    \qfdshowimportancetrue
\newif\ifqfdshowcorrlegend    \qfdshowcorrlegendtrue
\newif\ifqfdshowevallegend    \qfdshowevallegendtrue

\def\qfdNW{5}
\def\qfdNH{5}
\def\qfdWhatW{4.0}
\def\qfdImpW{0.9}
\def\qfdCmpW{3}
\def\qfdHdrH{2.6}
\def\qfdBasementN{4}

\def\qfdWhatsTitle{Customer needs}
\def\qfdImpTitle{Imp.\ \%}
\def\qfdPerceptionTitle{Comparative evaluation}
\def\qfdPoorLabel{poor}
\def\qfdExcellentLabel{excellent}
\def\qfdAltOneLabel{Our product}
\def\qfdAltTwoLabel{Competitor A}
\def\qfdAltThreeLabel{Competitor B}
\def\qfdRelTitle{Relation}
\def\qfdCorrTitle{Correlation}
\def\qfdEvalTitle{Evaluation}

\tikzset{
  qfdthin/.style ={line width=0.35pt},
  qfdmed/.style  ={line width=0.7pt},
  qfdstrong/.style={circle, draw, fill=black,
                    minimum size=7pt, inner sep=0pt},
  qfdmod/.style  ={circle, draw,
                    minimum size=7pt, inner sep=0pt, line width=0.8pt},
  qfdweak/.style ={regular polygon, regular polygon sides=3, draw,
                    minimum size=8.5pt, inner sep=0pt, line width=0.7pt},
  qfdrel/.is choice,
  qfdrel/S/.style={qfdstrong},
  qfdrel/M/.style={qfdmod},
  qfdrel/W/.style={qfdweak},
  qfdalt1mk/.style={circle, draw, fill=black,
                    minimum size=6pt, inner sep=0pt, line width=1pt},
  qfdalt1ln/.style={line width=1.2pt},
  qfdalt2mk/.style={regular polygon, regular polygon sides=3, draw,
                    fill=black, minimum size=6pt, inner sep=0pt,
                    line width=0.7pt},
  qfdalt2ln/.style={line width=0.7pt, dashed},
  qfdalt3mk/.style={rectangle, draw, fill=black,
                    minimum size=5pt, inner sep=0pt, line width=0.7pt},
  qfdalt3ln/.style={line width=0.7pt, dotted},
}

\newcommand{\qfdDrawGrid}{%
  \foreach \c in {1,...,\qfdNHm} \draw[qfdthin] (\c, 0) -- (\c, -\qfdNW);
  \foreach \r in {1,...,\qfdNWm} \draw[qfdthin] (0, -\r) -- (\qfdNH, -\r);
  \foreach \r in {1,...,\qfdNWm}
    \draw[qfdthin] (\qfdLeftEdge, -\r) -- (0, -\r);
  \ifqfdshowroof
    \foreach \c in {1,...,\qfdNHm}
      \draw[qfdthin] (\c, 0) -- (\c, \qfdHdrH);
  \fi
  \ifqfdshowcompetitive
    \foreach \r in {1,...,\qfdNWm}
      \draw[qfdthin] (\qfdNH, -\r) -- (\qfdNH+\qfdCmpW, -\r);
  \fi
  \ifqfdshowbasement
    \foreach \r in {1,...,\qfdBasementN}
      \draw[qfdthin] (0, -\qfdNW-\r) -- (\qfdNH, -\qfdNW-\r);
    \foreach \c in {1,...,\qfdNHm}
      \draw[qfdthin] (\c, -\qfdNW) -- (\c, -\qfdNW-\qfdBasementN);
  \fi
}

\newcommand{\qfdDrawRoof}{%
  \ifqfdshowroof
    \foreach \k in {1,...,\qfdNHm} {%
      \pgfmathsetmacro{\rx}{(\k+\qfdNH)/2}
      \pgfmathsetmacro{\ry}{\qfdHdrH + (\qfdNH-\k)/2}
      \pgfmathsetmacro{\lx}{\k/2}
      \pgfmathsetmacro{\ly}{\qfdHdrH + \k/2}
      \draw[qfdthin] (\k, \qfdHdrH) -- (\rx, \ry);
      \draw[qfdthin] (\k, \qfdHdrH) -- (\lx, \ly);
    }%
    \draw[qfdmed] (0, \qfdHdrH)
       -- (\qfdNH/2, \qfdApexY) -- (\qfdNH, \qfdHdrH);
    \foreach \i in {1,...,\qfdNH}
      \foreach \k in {1,...,\qfdNH} {%
        \pgfmathtruncatemacro{\jj}{\i+\k}
        \ifnum\jj>\qfdNH\relax\else
          \pgfmathsetmacro{\xx}{\i + \k/2 - 0.5}
          \pgfmathsetmacro{\yy}{\qfdHdrH + \k/2}
          \coordinate (C-\i-\jj) at (\xx, \yy);
        \fi
      }%
  \fi
}

\newcommand{\qfdDrawScale}{%
  \ifqfdshowcompetitive
    \foreach \tk in {0,1,2,3,4,5} {%
      \pgfmathsetmacro{\tx}{\qfdNH + (\tk+0.5)*\qfdCmpW/6}
      \node[anchor=south, font=\scriptsize] at (\tx, 0.02) {\tk};
    }%
    \node[anchor=south, font=\scriptsize\bfseries, align=center]
         at ({\qfdNH + \qfdCmpW/2}, 0.7) {\qfdPerceptionTitle};
    \node[anchor=north, font=\scriptsize\itshape]
         at ({\qfdNH + 0.45}, -\qfdNW) {\qfdPoorLabel};
    \node[anchor=north, font=\scriptsize\itshape]
         at ({\qfdNH + \qfdCmpW - 0.45}, -\qfdNW) {\qfdExcellentLabel};
  \fi
}

\newcommand{\qfdDrawZoneTitles}{%
  \ifqfdshowimportance
    \node[rotate=90, anchor=west, font=\footnotesize\bfseries]
         at ({-\qfdImpW/2}, 0.12) {\qfdImpTitle};
  \fi
  \node[font=\scriptsize\bfseries, align=center, text width=\qfdWhatW cm]
       at ({\qfdLeftEdge + \qfdWhatW/2},
           {\ifqfdshowroof \qfdHdrH/2 \else 0.6 \fi}) {\qfdWhatsTitle};
}

\newcommand{\qfdDrawFrames}{%
  \begin{scope}[qfdmed]
    \draw (\qfdLeftEdge, 0) rectangle (\qfdNH, -\qfdNW);
    \ifqfdshowimportance \draw (-\qfdImpW, 0) -- (-\qfdImpW, -\qfdNW); \fi
    \draw (0, 0) -- (0, -\qfdNW);
    \ifqfdshowroof
      \draw (0, 0) rectangle (\qfdNH, \qfdHdrH); \fi
    \ifqfdshowbasement
      \draw (0, -\qfdNW) rectangle (\qfdNH, -\qfdNW-\qfdBasementN); \fi
    \ifqfdshowcompetitive
      \draw (\qfdNH, 0) rectangle (\qfdNH+\qfdCmpW, -\qfdNW); \fi
  \end{scope}
}

\newcommand{\qfdDrawLegend}{%
  \ifqfdshowlegend
    \pgfmathsetmacro{\qfdLegX}{%
      \qfdNH + \ifqfdshowcompetitive \qfdCmpW + 0.7 \else 0.7 \fi}
    \pgfmathsetmacro{\qfdLegBottom}{%
      -2.05
      \ifqfdshowroof    \ifqfdshowcorrlegend - 2.55 \fi \fi
      \ifqfdshowcompetitive \ifqfdshowevallegend - 2.20 \fi \fi}
    \pgfmathsetmacro{\qfdLegY}{\qfdHdrH - 0.4}
    \begin{scope}[shift={(\qfdLegX, \qfdLegY)}]
      \draw[qfdmed, rounded corners=2pt]
        (-0.15, 0.4) rectangle (4.5, \qfdLegBottom);
      \node[anchor=west, font=\footnotesize\bfseries] at (0, 0.1)
        {\qfdRelTitle};
      \draw[qfdthin] (0, -0.15) -- (4.35, -0.15);
      \node[qfdstrong] at (0.22, -0.5)  {};
        \node[anchor=west] at (0.5, -0.5)  {Strong (9)};
      \node[qfdmod]    at (0.22, -0.95) {};
        \node[anchor=west] at (0.5, -0.95) {Medium (3)};
      \node[qfdweak]   at (0.22, -1.4)  {};
        \node[anchor=west] at (0.5, -1.4)  {Weak (1)};
      \ifqfdshowroof \ifqfdshowcorrlegend
        \node[anchor=west, font=\footnotesize\bfseries] at (0, -2.10)
          {\qfdCorrTitle};
        \draw[qfdthin] (0, -2.35) -- (4.35, -2.35);
        \node[anchor=west] at (0, -2.70) {{$+\!+$}\quad very positive};
        \node[anchor=west] at (0, -3.05) {{$+$\phantom{$+$}}\quad positive};
        \node[anchor=west] at (0, -3.40) {{$-$\phantom{$-$}}\quad negative};
        \node[anchor=west] at (0, -3.75) {{$-\!-$}\quad very negative};
      \fi \fi
      \ifqfdshowcompetitive \ifqfdshowevallegend
        \pgfmathsetmacro{\qfdEvalTop}{%
          -2.10 \ifqfdshowroof\ifqfdshowcorrlegend - 2.55 \fi\fi}
        \node[anchor=west, font=\footnotesize\bfseries]
          at (0, \qfdEvalTop) {\qfdEvalTitle};
        \pgfmathsetmacro{\qfdEvalSep}{\qfdEvalTop - 0.25}
        \draw[qfdthin] (0, \qfdEvalSep) -- (4.35, \qfdEvalSep);
        \pgfmathsetmacro{\qfdLegA}{\qfdEvalTop - 0.55}
        \draw[qfdalt1ln] (0.05, \qfdLegA) -- (0.45, \qfdLegA);
          \node[qfdalt1mk] at (0.25, \qfdLegA) {};
          \node[anchor=west, font=\bfseries] at (0.55, \qfdLegA)
            {\qfdAltOneLabel};
        \pgfmathsetmacro{\qfdLegB}{\qfdEvalTop - 0.95}
        \draw[qfdalt2ln] (0.05, \qfdLegB) -- (0.45, \qfdLegB);
          \node[qfdalt2mk] at (0.25, \qfdLegB) {};
          \node[anchor=west] at (0.55, \qfdLegB) {\qfdAltTwoLabel};
        \pgfmathsetmacro{\qfdLegC}{\qfdEvalTop - 1.35}
        \draw[qfdalt3ln] (0.05, \qfdLegC) -- (0.45, \qfdLegC);
          \node[qfdalt3mk] at (0.25, \qfdLegC) {};
          \node[anchor=west] at (0.55, \qfdLegC) {\qfdAltThreeLabel};
      \fi \fi
    \end{scope}
  \fi
}

\newenvironment{qfdhouse}{%
  \begin{tikzpicture}[x=1cm, y=1cm, font=\scriptsize,
                      line cap=round, line join=round]
  \ifqfdshowimportance
    \pgfmathsetmacro{\qfdLeftEdge}{-\qfdWhatW-\qfdImpW}
  \else
    \pgfmathsetmacro{\qfdLeftEdge}{-\qfdWhatW}
  \fi
  \pgfmathsetmacro{\qfdApexY}{\qfdHdrH + \qfdNH/2}
  \pgfmathtruncatemacro{\qfdNHm}{\qfdNH - 1}
  \pgfmathtruncatemacro{\qfdNWm}{\qfdNW - 1}
  \qfdDrawGrid
  \qfdDrawRoof
  \qfdDrawScale
  \qfdDrawZoneTitles
}{%
  \qfdDrawFrames
  \qfdDrawLegend
  \end{tikzpicture}%
}

% --- Dimensions tuned for the typewriter QFD (13 W x 15 H) ---
\def\qfdNW{13}
\def\qfdNH{15}
\def\qfdWhatW{4.6}
\def\qfdImpW{0.7}
\def\qfdHdrH{3.2}
\def\qfdBasementN{3}
\def\qfdCmpW{3.4}
\qfdshowlegendfalse                 % we draw a 4-alternative legend manually

\def\qfdWhatsTitle{User-facing requirements (W)}
\def\qfdImpTitle{Weight}
\def\qfdPerceptionTitle{Competitive perception (0–5, guessed)}
\def\qfdPoorLabel{poor}
\def\qfdExcellentLabel{excellent}

% Perception-zone markers: shape + colour-blind-safe colour per product.
% Palette is Okabe-Ito (blue, vermillion, bluish green, reddish purple).
% Light fills + saturated outlines keep stacked markers legible.
\definecolor{qfdcOurs}{RGB}{0,114,178}
\definecolor{qfdcRem}{RGB}{213,94,0}
\definecolor{qfdcFrw}{RGB}{0,158,115}
\definecolor{qfdcPom}{RGB}{204,121,167}

\tikzset{
  qfdalt1mk/.style={circle, draw=qfdcOurs, fill=qfdcOurs!55!white,
                    minimum size=6.5pt, inner sep=0pt, line width=1.1pt},
  qfdalt1ln/.style={line width=1.2pt, qfdcOurs},
  qfdalt2mk/.style={regular polygon, regular polygon sides=3,
                    draw=qfdcRem, fill=qfdcRem!55!white,
                    minimum size=7pt, inner sep=0pt, line width=0.9pt},
  qfdalt2ln/.style={line width=0.8pt, dashed, qfdcRem},
  qfdalt3mk/.style={rectangle, draw=qfdcFrw, fill=qfdcFrw!55!white,
                    minimum size=5.5pt, inner sep=0pt, line width=0.9pt},
  qfdalt3ln/.style={line width=0.8pt, dotted, qfdcFrw},
  qfdalt4mk/.style={diamond, aspect=1, draw=qfdcPom,
                    fill=qfdcPom!50!white,
                    minimum size=7pt, inner sep=0pt, line width=1.0pt},
  qfdalt4ln/.style={line width=0.8pt, dash dot, qfdcPom},
}

\begin{document}
\begin{qfdhouse}

  % ---------- WHATs (left column) ----------
  \foreach \r/\t in {%
    1/{W1 Sub-second visible response to typing},
    2/{W2 Publishing is one deliberate action away},
    3/{W3 Pulling power never corrupts the file},
    4/{W4 Provisioning never interrupts a writing session},
    5/{W5 Quick boot to a writing cursor},
    6/{W6 Long sessions without crash, lag, drift},
    7/{W7 Nothing on the device competes with prose},
    8/{W8 The UI never moves except when I move it},
    9/{W9 Codebase absorbs the planned roadmap},
    10/{W10 I can repair or fork it with hobbyist tools},
    11/{W11 Multi-day battery life (v0.8 onward)},
    12/{W12 Local-only files coexist with git scope (v0.5+)},
    13/{W13 Typography sets a writing-tool tone}%
  }
    \node[anchor=west, font=\scriptsize, text width=\qfdWhatW cm,
          align=left]
      at ({\qfdLeftEdge + 0.1}, {-\r + 0.5}) {\t};

  % ---------- Importance (raw 1-10 weight) ----------
  \foreach \r/\w in {1/10, 2/9, 3/10, 4/7, 5/6, 6/9, 7/8, 8/7,
                     9/8, 10/5, 11/4, 12/5, 13/7}
    \node[font=\scriptsize] at ({-\qfdImpW/2}, {-\r + 0.5}) {\w};

  % ---------- HOWs (rotated column titles) ----------
  \foreach \c/\t in {%
    1/{H1 Keypress$\to$glyph latency},
    2/{H2 Refresh area per keystroke},
    3/{H3 Full-refresh cadence},
    4/{H4 Cold boot to cursor},
    5/{H5 Continuous-typing endurance},
    6/{H6 Push success rate},
    7/{H7 Push end-to-end time},
    8/{H8 Save durability vs power loss},
    9/{H9 PSRAM heap headroom},
    10/{H10 Firmware binary size},
    11/{H11 Total stack budget},
    12/{H12 Wi-Fi reconnect time},
    13/{H13 Idle / typing / push current},
    14/{H14 Module / API surface count},
    15/{H15 Clean release build time}%
  }
    \node[rotate=90, anchor=west, font=\scriptsize]
      at ({\c - 0.5}, 0.15) {\t};

  % ---------- Relation matrix (S=9, M=3, W=1) ----------
  % W1 row 1: H1S H2S H3M H5M H9W H11W
  \node[qfdrel/S] at ({1 - 0.5},  {-1 + 0.5}) {};
  \node[qfdrel/S] at ({2 - 0.5},  {-1 + 0.5}) {};
  \node[qfdrel/M] at ({3 - 0.5},  {-1 + 0.5}) {};
  \node[qfdrel/M] at ({5 - 0.5},  {-1 + 0.5}) {};
  \node[qfdrel/W] at ({9 - 0.5},  {-1 + 0.5}) {};
  \node[qfdrel/W] at ({11 - 0.5}, {-1 + 0.5}) {};

  % W2 row 2: H6S H7M H9S H12S
  \node[qfdrel/S] at ({6 - 0.5},  {-2 + 0.5}) {};
  \node[qfdrel/M] at ({7 - 0.5},  {-2 + 0.5}) {};
  \node[qfdrel/S] at ({9 - 0.5},  {-2 + 0.5}) {};
  \node[qfdrel/S] at ({12 - 0.5}, {-2 + 0.5}) {};

  % W3 row 3: H8S
  \node[qfdrel/S] at ({8 - 0.5},  {-3 + 0.5}) {};

  % W4 row 4: H6M H12M H14W
  \node[qfdrel/M] at ({6 - 0.5},  {-4 + 0.5}) {};
  \node[qfdrel/M] at ({12 - 0.5}, {-4 + 0.5}) {};
  \node[qfdrel/W] at ({14 - 0.5}, {-4 + 0.5}) {};

  % W5 row 5: H4S H10M
  \node[qfdrel/S] at ({4 - 0.5},  {-5 + 0.5}) {};
  \node[qfdrel/M] at ({10 - 0.5}, {-5 + 0.5}) {};

  % W6 row 6: H1M H3M H5S H6M H8M H9S H11M H12M
  \node[qfdrel/M] at ({1 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/M] at ({3 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/S] at ({5 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/M] at ({6 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/M] at ({8 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/S] at ({9 - 0.5},  {-6 + 0.5}) {};
  \node[qfdrel/M] at ({11 - 0.5}, {-6 + 0.5}) {};
  \node[qfdrel/M] at ({12 - 0.5}, {-6 + 0.5}) {};

  % W7 row 7: H1M H2M H3M H13M H14W
  \node[qfdrel/M] at ({1 - 0.5},  {-7 + 0.5}) {};
  \node[qfdrel/M] at ({2 - 0.5},  {-7 + 0.5}) {};
  \node[qfdrel/M] at ({3 - 0.5},  {-7 + 0.5}) {};
  \node[qfdrel/M] at ({13 - 0.5}, {-7 + 0.5}) {};
  \node[qfdrel/W] at ({14 - 0.5}, {-7 + 0.5}) {};

  % W8 row 8: H1W H2S H3S
  \node[qfdrel/W] at ({1 - 0.5},  {-8 + 0.5}) {};
  \node[qfdrel/S] at ({2 - 0.5},  {-8 + 0.5}) {};
  \node[qfdrel/S] at ({3 - 0.5},  {-8 + 0.5}) {};

  % W9 row 9: H10W H11W H14S H15M
  \node[qfdrel/W] at ({10 - 0.5}, {-9 + 0.5}) {};
  \node[qfdrel/W] at ({11 - 0.5}, {-9 + 0.5}) {};
  \node[qfdrel/S] at ({14 - 0.5}, {-9 + 0.5}) {};
  \node[qfdrel/M] at ({15 - 0.5}, {-9 + 0.5}) {};

  % W10 row 10: H10M H13W H14M H15W
  \node[qfdrel/M] at ({10 - 0.5}, {-10 + 0.5}) {};
  \node[qfdrel/W] at ({13 - 0.5}, {-10 + 0.5}) {};
  \node[qfdrel/M] at ({14 - 0.5}, {-10 + 0.5}) {};
  \node[qfdrel/W] at ({15 - 0.5}, {-10 + 0.5}) {};

  % W11 row 11: H13S
  \node[qfdrel/S] at ({13 - 0.5}, {-11 + 0.5}) {};

  % W12 row 12: H6W H8M H14M
  \node[qfdrel/W] at ({6 - 0.5},  {-12 + 0.5}) {};
  \node[qfdrel/M] at ({8 - 0.5},  {-12 + 0.5}) {};
  \node[qfdrel/M] at ({14 - 0.5}, {-12 + 0.5}) {};

  % W13 row 13: H9M
  \node[qfdrel/M] at ({9 - 0.5},  {-13 + 0.5}) {};

  % ---------- Roof correlations ----------
  \node[font=\scriptsize] at (C-1-2)   {$+\!+$};   % H1-H2 strong reinforce
  \node[font=\scriptsize] at (C-1-3)   {$-$};      % H1-H3 mild conflict
  \node[font=\scriptsize] at (C-1-5)   {$+$};      % H1-H5 mild reinforce
  \node[font=\scriptsize] at (C-1-13)  {$-$};      % H1-H13 mild conflict
  \node[font=\scriptsize] at (C-2-3)   {$+\!+$};   % H2-H3 strong reinforce
  \node[font=\scriptsize] at (C-2-13)  {$+$};      % H2-H13
  \node[font=\scriptsize] at (C-3-13)  {$+$};      % H3-H13
  \node[font=\scriptsize] at (C-4-10)  {$-$};      % H4-H10 boot vs binary
  \node[font=\scriptsize] at (C-5-6)   {$+$};      % H5-H6
  \node[font=\scriptsize] at (C-5-8)   {$+$};      % H5-H8
  \node[font=\scriptsize] at (C-5-9)   {$-\!-$};   % H5-H9 soak vs heap
  \node[font=\scriptsize] at (C-6-7)   {$+$};      % H6-H7
  \node[font=\scriptsize] at (C-6-9)   {$-\!-$};   % H6-H9 push vs heap
  \node[font=\scriptsize] at (C-6-12)  {$+\!+$};   % H6-H12
  \node[font=\scriptsize] at (C-7-9)   {$-$};      % H7-H9
  \node[font=\scriptsize] at (C-7-12)  {$+\!+$};   % H7-H12
  \node[font=\scriptsize] at (C-9-10)  {$-\!-$};   % H9-H10 heap vs binary
  \node[font=\scriptsize] at (C-10-15) {$-\!-$};   % H10-H15 binary vs build
  \node[font=\scriptsize] at (C-11-13) {$-$};      % H11-H13
  \node[font=\scriptsize] at (C-14-15) {$-$};      % H14-H15 modularity vs build

  % ---------- Basement: target / abs weight / rel weight % ----------
  \foreach \c/\tgt/\abs/\rel in {%
    1/{$\leq$200\,ms}/148/10,
    2/{$\leq$1 line}/177/11,
    3/{1 : 20}/144/9,
    4/{$\leq$5\,s}/54/3,
    5/{$\geq$1\,h}/111/7,
    6/{$\geq$95\,\%}/134/9,
    7/{$\leq$30\,s}/27/2,
    8/{100\,\%}/132/9,
    9/{$\geq$1\,MB}/193/12,
    10/{$\leq$2\,MB}/41/3,
    11/{$\leq$80\,KB}/45/3,
    12/{$\leq$30\,s}/129/8,
    13/{obs.}/65/4,
    14/{$\leq$8}/117/8,
    15/{$\leq$7\,min}/29/2%
  } {
    \node[font=\scriptsize] at ({\c - 0.5}, {-\qfdNW - 0.5}) {\tgt};
    \node[font=\scriptsize] at ({\c - 0.5}, {-\qfdNW - 1.5}) {\abs};
    \node[font=\scriptsize\bfseries]
      at ({\c - 0.5}, {-\qfdNW - 2.5}) {\rel};
  }

  % ---------- Basement row labels (in the margin below WHATs) ----------
  \foreach \k/\lbl in {1/{Target (v0.1)}, 2/{$\Sigma$ abs}, 3/{Rel.\ \%}}
    \node[anchor=east, font=\scriptsize\itshape]
      at ({-0.1}, {-\qfdNW - \k + 0.5}) {\lbl};

  % ---------- Perception zone: 4 products x 13 WHATs (0-5 scores) ----------
  % Columns: \so=Ours target, \st=reMarkable 2 + Type Folio,
  %          \sf=Freewrite Traveler, \sg=Pomera DM250.
  \foreach \r/\so/\st/\sf/\sg in {%
    1/4/3/3/5,
    2/5/4/4/2,
    3/4/4/2/2,
    4/5/2/2/5,
    5/4/3/3/5,
    6/3/3/4/5,
    7/5/2/5/5,
    8/4/3/4/5,
    9/4/3/1/1,
    10/5/4/2/1,
    11/1/5/5/4,
    12/3/1/2/3,
    13/3/5/2/2%
  } {
    \pgfmathsetmacro{\xo}{\qfdNH + (\so + 0.5)*\qfdCmpW/6}
    \pgfmathsetmacro{\xt}{\qfdNH + (\st + 0.5)*\qfdCmpW/6}
    \pgfmathsetmacro{\xf}{\qfdNH + (\sf + 0.5)*\qfdCmpW/6}
    \pgfmathsetmacro{\xg}{\qfdNH + (\sg + 0.5)*\qfdCmpW/6}
    \node[qfdalt1mk] at (\xo, {-\r + 0.5}) {};
    \node[qfdalt2mk] at (\xt, {-\r + 0.5}) {};
    \node[qfdalt3mk] at (\xf, {-\r + 0.5}) {};
    \node[qfdalt4mk] at (\xg, {-\r + 0.5}) {};
  }

  % ---------- Manual legend (4 alternatives, placed right of zones) ----------
  \pgfmathsetmacro{\qfdLegX}{\qfdNH + \qfdCmpW + 0.7}
  \begin{scope}[shift={(\qfdLegX, \qfdHdrH - 0.4)}]
    \draw[qfdmed, rounded corners=2pt]
      (-0.15, 0.4) rectangle (5.1, -7.05);
    % Relations
    \node[anchor=west, font=\footnotesize\bfseries] at (0, 0.1)
      {Relation};
    \draw[qfdthin] (0, -0.15) -- (4.95, -0.15);
    \node[qfdstrong] at (0.22, -0.5)  {};
      \node[anchor=west] at (0.5, -0.5)  {Strong (9)};
    \node[qfdmod]    at (0.22, -0.95) {};
      \node[anchor=west] at (0.5, -0.95) {Medium (3)};
    \node[qfdweak]   at (0.22, -1.4)  {};
      \node[anchor=west] at (0.5, -1.4)  {Weak (1)};
    % Correlation
    \node[anchor=west, font=\footnotesize\bfseries] at (0, -2.10)
      {Correlation};
    \draw[qfdthin] (0, -2.35) -- (4.95, -2.35);
    \node[anchor=west] at (0, -2.70) {{$+\!+$}\quad very positive};
    \node[anchor=west] at (0, -3.05) {{$+$\phantom{$+$}}\quad positive};
    \node[anchor=west] at (0, -3.40) {{$-$\phantom{$-$}}\quad negative};
    \node[anchor=west] at (0, -3.75) {{$-\!-$}\quad very negative};
    % Perception
    \node[anchor=west, font=\footnotesize\bfseries] at (0, -4.20)
      {Perception};
    \draw[qfdthin] (0, -4.45) -- (4.95, -4.45);
    \draw[qfdalt1ln] (0.05, -4.80) -- (0.45, -4.80);
      \node[qfdalt1mk] at (0.25, -4.80) {};
      \node[anchor=west, font=\bfseries] at (0.55, -4.80)
        {Ours (v0.1 target)};
    \draw[qfdalt2ln] (0.05, -5.25) -- (0.45, -5.25);
      \node[qfdalt2mk] at (0.25, -5.25) {};
      \node[anchor=west] at (0.55, -5.25) {reMarkable 2 + Type Folio};
    \draw[qfdalt3ln] (0.05, -5.70) -- (0.45, -5.70);
      \node[qfdalt3mk] at (0.25, -5.70) {};
      \node[anchor=west] at (0.55, -5.70) {Freewrite Traveler};
    \draw[qfdalt4ln] (0.05, -6.15) -- (0.45, -6.15);
      \node[qfdalt4mk] at (0.25, -6.15) {};
      \node[anchor=west] at (0.55, -6.15) {Pomera DM250};
    \node[anchor=west, font=\scriptsize\itshape] at (0, -6.70)
      {0 = poor, 5 = excellent};
  \end{scope}

\end{qfdhouse}
\end{document}

Perception scores (guessed)

Four products on the 0–5 scale, scored against each WHAT. Reference configurations: reMarkable 2 + Type Folio, Freewrite Traveler, Pomera DM250 (DM250 has a reflective monochrome LCD, not e-ink — flagged in W1 / W8). "Ours" is the v0.1 target from qfd.md §2, not measured yet.

ID	WHAT (truncated)	Ours	reM.	Frw.	Pom.	Rationale (shortest defensible)
W1	Sub-second response to typing	4	3	3	5	Ours targets ≤200 ms; reMarkable + Freewrite (e-ink) are visibly laggy; Pomera's reflective LCD is near-zero.
W2	Publishing is one deliberate action away	5	4	4	2	Ctrl-G atomic; reMarkable + Freewrite cloud-sync is one-tap but not git; Pomera = USB/SD copy or QR transfer.
W3	Pulling power never corrupts the file	4	4	2	2	Ours: atomic-rename + fsync. reMarkable journals. Freewrite + Pomera: forum reports of corruption on yank.
W4	Provisioning never interrupts writing	5	2	2	5	Ours v0.1: build-time config (dev-only). reM/Frw need Wi-Fi + account. Pomera: literally none.
W5	Quick boot to a writing cursor	4	3	3	5	Ours target ≤5 s. reMarkable cold-boots ~20 s (great from sleep). Pomera ~3 s.
W6	Long sessions without crash / lag / drift	3	3	4	5	Ours unproven (1 h target). Freewrite famously stable. Pomera firmware is decades-mature.
W7	Nothing on the device competes with prose	5	2	5	5	reMarkable has apps, menus, drawing, PDFs. Freewrite + Pomera are single-purpose; ours by design.
W8	The UI never moves except when I move it	4	3	4	5	reMarkable animates more; ours uses dirty-rects; Freewrite minimal motion; Pomera near-static LCD.
W9	Codebase absorbs the planned roadmap	4	3	1	1	Modular Rust ours; reMarkable is hackable Linux; Freewrite + Pomera are closed firmware.
W10	I can repair or fork it with hobbyist tools	5	4	2	1	Ours: open BOM + ESP32. reMarkable: rooted Linux + community ROMs. Freewrite + Pomera: closed.
W11	Multi-day battery life (v0.8 onward)	1	5	5	4	Ours v0.1 = wall-powered (battery deferred). reMarkable + Freewrite Traveler legendary. Pomera ~24 h.
W12	Local-only files coexist with git scope	3	1	2	3	Ours v0.5+ design. reMarkable cloud-only. Freewrite has local + Postbox but no VCS. Pomera = pure local.
W13	Typography sets a writing-tool tone	3	5	2	2	Ours v0.1: single mono (serif option in v1.0). reMarkable: rich type rendering. Freewrite + Pomera: utilitarian.

Totals (sum across 13 WHATs, no weighting): Ours 50, Pomera 45, reMarkable 42, Freewrite 39. Pomera ranking second is the useful signal — we're effectively building "Pomera + Wi-Fi + git + hackable BOM", which re-confirms the differentiation thesis from README.md.

Weighted totals (Σ score × W weight) tell the same story with more contrast — left as exercise; the unweighted view is enough to read the picture.

Caveats

• Single-rater bias. All thirteen rows are scored from the project author's POV. A reMarkable buyer would weight W11 (battery) at 10 and W12 (git) at 1, flipping the totals.
• Configuration matters. Freewrite Smart Typewriter (e-ink) scores differently from Traveler (LCD) on W1 / W5. The table picks Traveler as the most direct competitor.
• W3 / W6 Freewrite scores are anecdotal. Forum reports, not bench data. Treat the 2 / 4 as "we'd need to test this" rather than fact.
• No price column. Ours-as-BOM is materially cheaper than the competitors but cost is not a WHAT in qfd.md §1, so it's absent here. Worth a row if a v0.x WHAT ever calls it out.

Reading the house

• Importance (left column) is the raw 1–10 weight from qfd.md §1, not a normalised %, so adding stays cheap when a WHAT shifts. Sum of weights is 95; treat each unit as ~1.05 % if you want a percentage view.
• Roof carries the §4 symbols translated into classical QFD glyphs: ++ strong reinforcement (◎), + mild reinforcement (○), − mild conflict (×), −− strong conflict (⊗).
• Basement rows are: v0.1 target → §3 column sum (Σ of weight × strength) → relative weight as integer % of total (1546). Relative weights round to 100.
• H7, H10, H15 (push time, binary size, build time) sit at the bottom of the basement — knowingly-paid costs per qfd.md §7, not signals to optimise harder.

Regenerating

The matrix cells (\node[qfdrel/{S,M,W}]), roof symbols (C-i-j slots), and basement Σ + Rel% are native to this file — re-score directly in the TikZ source, then update the §3 priority list and §4 conflict list in qfd.md to match the new picture.

When qfd.md §1 or §2 changes:

1. Importance column → §1 weight column.
2. HOW titles + v0.1 targets → §2 target column.
3. Recompute basement Σ for any HOW whose column changed: per-cell contribution = (W weight) × (cell strength: 9 / 3 / 1 / 0).
4. Recompute relative weight: each Σ ÷ total Σ × 100, rounded to integer percent.

Perception scores are not derived from qfd.md — they live only in this file. Update them when (a) a competitor ships a relevant change, (b) measurement replaces a guess, or (c) a WHAT is added/removed in §1. Each score keeps its one-line rationale in the table above.

If a renderer rejects the tikz fence, the file is still readable as source — the placement comments name each WHAT, HOW, and cell. The perception-scores table above is the human-readable fallback for the right-hand zone of the diagram.