Eliminate opposing walls

src/math/Interator3.zig

@@ -0,0 +1,42 @@
+pub fn Interator3(comptime T: type) type {
+    return struct {
+        const Self = @This();
+        const Vector = @Vector(3, T);
+
+        min: Vector,
+        max: Vector,
+        current: ?Vector,
+
+        pub fn init(min_x: T, min_y: T, min_z: T, max_x: T, max_y: T, max_z: T) Self {
+            const min: Vector = .{ min_x, min_y, min_z };
+            const max: Vector = .{ max_x, max_y, max_z };
+            return .{
+                .min = min,
+                .max = max,
+                .current = min,
+            };
+        }
+
+        pub fn next(self: *Self) ?[3]T {
+            const current = self.current orelse return null;
+            var next_current = current;
+
+            next_current[0] = next_current[0] + 1;
+            if (next_current[0] > self.max[0]) {
+                next_current[0] = self.min[0];
+                next_current[1] = next_current[1] + 1;
+                if (next_current[1] > self.max[1]) {
+                    next_current[1] = self.min[1];
+                    next_current[2] = next_current[2] + 1;
+                    if (next_current[2] > self.max[2]) {
+                        self.current = null;
+                        return current;
+                    }
+                }
+            }
+
+            self.current = next_current;
+            return current;
+        }
+    };
+}