1-indexed rows where the ith row has 2i - 1 unit equilateral triangles.

The triangles in the ith row are also 1-indexed with coordinates from (i, 1) to (i, 2i - 1). The following image shows a triangle of side length 4 with the indexing of its triangle.

Two triangles are neighbors if they share a side. For example:

Triangles (1,1) and (2,2) are neighbors
Triangles (3,2) and (3,3) are neighbors.
Triangles (2,2) and (3,3) are not neighbors because they do not share any side.

Initially, all the unit triangles are white. You want to choose

Related Tags