def combine(wavs):
    output = zeros(len(wavs[0]))
    for i in range(len(wavs[0])):
        for a in range(len(wavs)):
            output[i] = output[i] + wavs[a][i]
    output = output/len(wavs)
    return output

search(input_grid, flow_grid, space):
  if space has flow or cannot flow:
    return
  if space doesn't have flow and can flow:
    mark space with flow
    search neighbors (which neighbors depends on which type of percolation)

percolation(input_grid):
  initialize flow_grid to all ones
  search from every square in the top row
  check bottom row for flow