diff --git a/index.html b/index.html
index e889079..16840fe 100644
--- a/index.html
+++ b/index.html
@@ -31,6 +31,11 @@
         <input id="scale" type="number" min="1" value="40">
         px per module
       </label>
+      <label for="gap">
+        <span>Grid gap:</span>
+        <input id="gap" type="number" min="0" value="0">
+        px between modules
+      </label>
       <button id="gen-btn">Generate</button>
     </div>
     <div>
diff --git a/script.js b/script.js
index 59f8fa5..63413ec 100644
--- a/script.js
+++ b/script.js
@@ -3,6 +3,50 @@ function intDiv(a, b) {
   return ~~(a / b)
 }
 
+let getCodeVersion
+
+const alignmentCoords = [
+  [6, 18],
+  [6, 22],
+  [6, 26],
+  [6, 30],
+  [6, 34],
+  [6, 22, 38],
+  [6, 24, 42],
+  [6, 26, 46],
+  [6, 28, 50],
+  [6, 30, 54],
+  [6, 32, 58],
+  [6, 34, 62],
+  [6, 26, 46, 66],
+  [6, 26, 48, 70],
+  [6, 26, 50, 74],
+  [6, 30, 54, 78],
+  [6, 30, 56, 82],
+  [6, 30, 58, 86],
+  [6, 34, 62, 90],
+  [6, 28, 50, 72, 94],
+  [6, 26, 50, 74, 98],
+  [6, 30, 54, 78, 102],
+  [6, 28, 54, 80, 106],
+  [6, 32, 58, 84, 110],
+  [6, 30, 58, 86, 114],
+  [6, 34, 62, 90, 118],
+  [6, 26, 50, 74, 98, 122],
+  [6, 30, 54, 78, 102, 126],
+  [6, 26, 52, 78, 104, 130],
+  [6, 30, 56, 82, 108, 134],
+  [6, 34, 60, 86, 112, 138],
+  [6, 30, 58, 86, 114, 142],
+  [6, 34, 62, 90, 118, 146],
+  [6, 30, 54, 78, 102, 126, 150],
+  [6, 24, 50, 76, 102, 128, 154],
+  [6, 28, 54, 80, 106, 132, 158],
+  [6, 32, 58, 84, 110, 136, 162],
+  [6, 26, 54, 82, 110, 138, 166],
+  [6, 30, 58, 86, 114, 142, 170],
+]
+
 addEventListener('DOMContentLoaded', () => {
   const canvas = document.getElementById("canvas")
   const ctx = canvas.getContext("2d")
@@ -13,24 +57,73 @@ addEventListener('DOMContentLoaded', () => {
     size: document.getElementById("width"),
     ver: document.getElementById("version"),
     scale: document.getElementById("scale"),
+    gap: document.getElementById("gap"),
   }
 
   document.getElementById("gen-btn").addEventListener("click", () => {
     const mask = options.mask.value
-    const size = options.size.value
-    const scale = options.scale.value
+    const size = Number(options.size.value)
+    const scale = Number(options.scale.value)
+    const gap = Math.min(Number(options.gap.value), scale) // not more than 1 module scaled size
+
+    const wh = scale - gap * 2 // width&height for 1 module with grid gap
 
     canvas.width = canvas.height = size * scale
 
     ctx.clearRect(0, 0, canvas.width, canvas.height)
+    ctx.fillStyle = "black"
 
     for (let row = 0; row < size; row++) {
       for (let col = 0; col < size; col++) {
         if (eval(mask) == 0) {
-          ctx.fillRect(col * scale, row * scale, scale, scale)
+          ctx.fillRect(col * scale + gap, row * scale + gap, wh, wh)
         }
       }
     }
+
+    const idSize = 8 * scale
+
+    { // finder pattern
+      ctx.fillStyle = "rgba(224, 63, 102, 0.5)"
+
+      ctx.fillRect(0, 0, idSize, idSize)
+      ctx.fillRect(canvas.width - idSize, 0, idSize, idSize)
+      ctx.fillRect(0, canvas.height - idSize, idSize, idSize)
+    }
+
+    const ver = getCodeVersion()
+
+    if (ver > 1) { // alignment pattern
+      ctx.fillStyle = "rgba(209, 63, 224, 0.5)"
+
+      const alignSize = 5 * scale
+      const coords = alignmentCoords[ver - 2] // array begins with version 2
+      const len = coords.length
+
+      for (let i = 0; i < len; i++) {
+        for (let j = 0; j < len; j++) {
+          const row = coords[i], col = coords[j]
+          if (row < 8 && col < 8 || row < 8 && col > size - 8 || row > size - 8 && col < 8) {
+            // do not overlap with finder pattern
+            continue
+          }
+          ctx.fillRect((row - 2) * scale, (col - 2) * scale, alignSize, alignSize)
+        }
+      }
+    }
+
+    { // timing pattern
+      ctx.fillStyle = "rgba(76, 63, 224, 0.5)"
+
+      const idEndPos = 6 * scale
+      const betweenIds = canvas.width - idSize * 2
+      ctx.fillRect(idSize, idEndPos, betweenIds, scale)
+      ctx.fillRect(idEndPos, idSize, scale, betweenIds)
+    }
+
+    { // format info
+      // TODO
+    }
   })
 
   { // Choose best scale for screen height
@@ -45,7 +138,7 @@ addEventListener('DOMContentLoaded', () => {
     const MIN_VER = 1
     const MAX_VER = 40
 
-    const getCodeVersion = () => {
+    getCodeVersion = () => {
       const size = options.size.value
       return Math.floor((size - MICRO_4) / DIFF)
     }
diff --git a/style.css b/style.css
index a4d7014..9a807d6 100644
--- a/style.css
+++ b/style.css
@@ -3,14 +3,17 @@ body {
   padding: 0.5rem;
 }
 
-#options {
+body > div {
+  width: fit-content;
+  margin: auto;
+}
+
+body > div#options {
   display: flex;
   flex-direction: column;
   row-gap: 0.25rem;
 
-  width: fit-content;
   max-width: calc(100vw - 0.5rem * 2);
-  margin: auto;
 }
 
 select, input, button {
@@ -20,7 +23,7 @@ select, input, button {
 }
 
 input[type=number] {
-  width: calc(1rem * 4 + 0.125rem * 2);
+  width: calc(4rem + 0.125rem * 2);
 }
 
 label {
@@ -35,6 +38,11 @@ label#width-wrapper > button {
 }
 
 label > span:nth-child(1) {
-  width: calc(3.5rem);
+  width: 5rem;
   text-align: right;
 }
+
+canvas {
+  margin-top: 0.5rem;
+  border: 2px solid #555;
+}