overpopulation rules

src/modules/automata.js

@@ -91,6 +91,17 @@ function conwayRules(cell, neighbors) {
   return cell;
 }
 
+// variation on the game of life's rules,
+// where the overpopulation rule is ignored
+function overpopulationRules(cell, neighbors) {
+  // loneliness rule
+  if (cell === 1 && neighbors < 2) return 0;
+  // born when three live neighbors rule
+  if (cell === 0 && neighbors === 3) return 1;
+  // the cell remains the same if none apply
+  return cell;
+}
+
 // get the next evolution of a 2D CA initial state
 // Rules : Moore neighborhood
 function evolve2d(board, rulesFn) {
@@ -148,6 +159,7 @@ export {
   createBoard,
   create1dStateOneCell,
   conwayRules,
+  overpopulationRules,
   evolve1d,
   evolve2d,
 };

src/modules/preset.js

@@ -92,4 +92,18 @@ const initialStates = [
   },
 ];
 
-export { presetRuleset, initialStates };
+const preset2dRules = [
+  {
+    id: "conway",
+    name: "Conway's Game of Life",
+    description: "The most popular 2d automata",
+  },
+  {
+    id: "overpopulation",
+    name: "Overpopulation variation",
+    description:
+      "Variation on Conway's Game of Life *without* the overpopulation rule",
+  },
+];
+
+export { presetRuleset, initialStates, preset2dRules };