diff --git a/src/layers/renderers/drawCultures.ts b/src/layers/renderers/drawCultures.ts
index 4458a0ab..7090f417 100644
--- a/src/layers/renderers/drawCultures.ts
+++ b/src/layers/renderers/drawCultures.ts
@@ -1,41 +1,22 @@
-import {connectVertices} from "scripts/connectVertices";
+import * as d3 from "d3";
+
+import {getPaths} from "./utilts";
 
 export function drawCultures() {
   /* uses */ const {cells, vertices, cultures} = pack;
 
-  cults.selectAll("path").remove(); // cleanup
+  const getType = (cellId: number) => cells.culture[cellId];
+  const paths = getPaths(cells.c, cells.v, vertices, getType);
 
-  const used = new Uint8Array(cells.i.length);
-  const paths = new Array(cultures.length).fill("");
+  const getColor = (i: number) => i && (cultures[i] as ICulture).color;
 
-  for (const i of cells.i) {
-    if (!cells.culture[i]) continue;
-    if (used[i]) continue;
-    used[i] = 1;
-    const cultureId = cells.culture[i];
-    const onborder = cells.c[i].some(n => cells.culture[n] !== cultureId);
-    if (!onborder) continue;
-
-    const startingVertex = cells.v[i].find(v => vertices.c[v].some(i => cells.culture[i] !== cultureId));
-    if (startingVertex === undefined)
-      throw new Error(`Draw cultures: starting vertex for culture ${cultureId} is not found`);
-
-    const ofSameType = (cellId: number) => cells.culture[cellId] === cultureId;
-    const chain = connectVertices({vertices, startingVertex, ofSameType});
-
-    if (chain.length < 3) continue;
-    const points = chain.map(v => vertices.p[v]);
-
-    paths[cultureId] += "M" + points.join("L") + "Z";
-  }
-
-  const data = paths.map((p, i) => [p, i]).filter(d => d[0].length > 10);
-  cults
+  d3.select("#cults")
     .selectAll("path")
-    .data(data)
+    .remove()
+    .data(Object.entries(paths))
     .enter()
     .append("path")
-    .attr("d", d => d[0])
-    .attr("fill", d => cultures[d[1]].color)
-    .attr("id", d => "culture" + d[1]);
+    .attr("d", ([, path]) => path)
+    .attr("fill", ([i]) => getColor(Number(i)))
+    .attr("id", ([i]) => "culture" + i);
 }
diff --git a/src/layers/renderers/utilts.ts b/src/layers/renderers/utilts.ts
new file mode 100644
index 00000000..cf454606
--- /dev/null
+++ b/src/layers/renderers/utilts.ts
@@ -0,0 +1,40 @@
+import {connectVertices} from "scripts/connectVertices";
+
+export function getPaths(
+  cellNeighbors: number[][],
+  cellVertices: number[][],
+  vertices: IGraphVertices,
+  getType: (cellId: number) => number
+) {
+  const paths: Dict<string> = {};
+
+  function addPath(index: number, points: TPoints) {
+    if (!paths[index]) paths[index] = "";
+    paths[index] += "M" + points.join("L") + "Z";
+  }
+
+  const checkedCells = new Uint8Array(cellNeighbors.length);
+  for (let cellId = 0; cellId < cellNeighbors.length; cellId++) {
+    if (checkedCells[cellId]) continue;
+    if (!getType(cellId)) continue;
+    checkedCells[cellId] = 1;
+
+    const type = getType(cellId);
+    const ofSameType = (cellId: number) => getType(cellId) === type;
+
+    const isOnborder = cellNeighbors[cellId].some(cellId => !ofSameType(cellId));
+    if (!isOnborder) continue;
+
+    const startingVertex = cellVertices[cellId].find(v => vertices.c[v].some(cellId => !ofSameType(cellId)));
+    if (startingVertex === undefined) throw new Error(`getPath: starting vertex for cell ${cellId} is not found`);
+
+    const chain = connectVertices({vertices, startingVertex, ofSameType, checkedCellsMutable: checkedCells});
+
+    if (chain.length < 3) continue;
+    const points = chain.map(v => vertices.p[v]);
+
+    addPath(type, points);
+  }
+
+  return paths;
+}
diff --git a/src/scripts/connectVertices.ts b/src/scripts/connectVertices.ts
index 5fbd1b47..cec69aba 100644
--- a/src/scripts/connectVertices.ts
+++ b/src/scripts/connectVertices.ts
@@ -94,21 +94,34 @@ const CONNECT_VERTICES_MAX_ITERATIONS = 50000;
 export function connectVertices({
   vertices,
   startingVertex,
-  ofSameType
+  ofSameType,
+  checkedCellsMutable
 }: {
   vertices: IGraphVertices;
   startingVertex: number;
   ofSameType: (cellId: number) => boolean;
+  checkedCellsMutable?: Uint8Array;
 }) {
   const chain: number[] = []; // vertices chain to form a path
 
+  const addToChecked = (cellIds: number[]) => {
+    if (checkedCellsMutable) {
+      cellIds.forEach(cellId => {
+        checkedCellsMutable[cellId] = 1;
+      });
+    }
+  };
+
   let next = startingVertex;
   for (let i = 0; i === 0 || (next !== startingVertex && i < CONNECT_VERTICES_MAX_ITERATIONS); i++) {
     const previous = chain.at(-1);
     const current = next;
     chain.push(current);
 
-    const [c1, c2, c3] = vertices.c[current].map(ofSameType);
+    const neibCells = vertices.c[current];
+    addToChecked(neibCells);
+
+    const [c1, c2, c3] = neibCells.map(ofSameType);
     const [v1, v2, v3] = vertices.v[current];
 
     if (v1 !== previous && c1 !== c2) next = v1;
diff --git a/src/types/common.d.ts b/src/types/common.d.ts
index a8ccea8b..4d479105 100644
--- a/src/types/common.d.ts
+++ b/src/types/common.d.ts
@@ -6,6 +6,9 @@ interface Dict<T> {
   [key: string]: T;
 }
 
+// element of Object.entries
+type ObjectEntry<T> = [string, T];
+
 type UintArray = Uint8Array | Uint16Array | Uint32Array;
 type IntArray = Int8Array | Int16Array | Int32Array;