<?xml version="1.0" encoding="UTF-8"?>
<svg width="980" height="600" viewBox="0 0 980 600"
     xmlns="http://www.w3.org/2000/svg"
     font-family="Arial, sans-serif">
 
  <!-- Background -->
  <rect width="100%" height="100%" fill="#ffffff"/>
 
  <!-- Title -->
  <text x="490" y="50" text-anchor="middle"
        font-size="30" font-weight="bold">
    Substrate Flow Map — S → C ↔ H → So → A
  </text>
 
  <!-- Arrowhead Definition -->
  <defs>
    <marker id="arrow" markerWidth="10" markerHeight="10"
            refX="10" refY="3" orient="auto" fill="#000">
      <path d="M0,0 L10,3 L0,6 Z"/>
    </marker>
  </defs>
 
  <!-- Substrate Nodes -->
  <g font-size="26" font-weight="bold">
    <text x="150" y="200" text-anchor="middle">S</text>
    <text x="320" y="200" text-anchor="middle">C</text>
    <text x="490" y="200" text-anchor="middle">H</text>
    <text x="660" y="200" text-anchor="middle">So</text>
    <text x="830" y="200" text-anchor="middle">A</text>
  </g>
 
  <!-- Substrate Labels -->
  <g font-size="16">
    <text x="150" y="240" text-anchor="middle">Symbolic</text>
    <text x="320" y="240" text-anchor="middle">Cognitive</text>
    <text x="490" y="240" text-anchor="middle">Harmonic</text>
    <text x="660" y="240" text-anchor="middle">Social</text>
    <text x="830" y="240" text-anchor="middle">Atlas</text>
  </g>
 
  <!-- Flow Arrows -->
  <!-- S → C -->
  <line x1="170" y1="195" x2="300" y2="195"
        stroke="#000" stroke-width="3" marker-end="url(#arrow)"/>
  <text x="235" y="175" text-anchor="middle" font-size="16">S → C</text>
 
  <!-- C ↔ H -->
  <line x1="340" y1="195" x2="470" y2="195"
        stroke="#000" stroke-width="3" marker-end="url(#arrow)"/>
  <line x1="470" y1="205" x2="340" y2="205"
        stroke="#000" stroke-width="3" marker-end="url(#arrow)"/>
  <text x="405" y="175" text-anchor="middle" font-size="16">C ↔ H</text>
 
  <!-- H → So -->
  <line x1="510" y1="195" x2="640" y2="195"
        stroke="#000" stroke-width="3" marker-end="url(#arrow)"/>
  <text x="575" y="175" text-anchor="middle" font-size="16">H → So</text>
 
  <!-- So → A -->
  <line x1="680" y1="195" x2="810" y2="195"
        stroke="#000" stroke-width="3" marker-end="url(#arrow)"/>
  <text x="745" y="175" text-anchor="middle" font-size="16">So → A</text>
 
  <!-- Drift Pathways (D1–D4) -->
  <g font-size="14" fill="#444">
    <text x="235" y="300" text-anchor="middle">D1</text>
    <text x="405" y="300" text-anchor="middle">D2</text>
    <text x="575" y="300" text-anchor="middle">D3</text>
    <text x="745" y="300" text-anchor="middle">D4</text>
  </g>
 
  <line x1="235" y1="260" x2="235" y2="290"
        stroke="#888" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="405" y1="260" x2="405" y2="290"
        stroke="#888" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="575" y1="260" x2="575" y2="290"
        stroke="#888" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="745" y1="260" x2="745" y2="290"
        stroke="#888" stroke-width="2" marker-end="url(#arrow)"/>
 
  <!-- Recursion Lines (R1–R4) -->
  <g font-size="14" fill="#000">
    <text x="150" y="330" text-anchor="middle">R1</text>
    <text x="320" y="330" text-anchor="middle">R2</text>
    <text x="490" y="330" text-anchor="middle">R3</text>
    <text x="660" y="330" text-anchor="middle">R4</text>
  </g>
 
  <line x1="150" y1="260" x2="150" y2="320"
        stroke="#000" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="320" y1="260" x2="320" y2="320"
        stroke="#000" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="490" y1="260" x2="490" y2="320"
        stroke="#000" stroke-width="2" marker-end="url(#arrow)"/>
  <line x1="660" y1="260" x2="660" y2="320"
        stroke="#000" stroke-width="2" marker-end="url(#arrow)"/>
 
  <!-- Atlas Pull -->
  <text x="830" y="330" text-anchor="middle" font-size="16" fill="#444">
    Atlas Pull
  </text>
  <line x1="830" y1="260" x2="830" y2="320"
        stroke="#444" stroke-width="2" marker-end="url(#arrow)"/>
 
</svg>