# quickie "evaporate" effect

spesh_idx = 127

for frame, layer, x, y in TileIter(self):
    char = self.get_char_index_at(frame, layer, x, y)
    if char != spesh_idx and char != 0:
        self.set_char_index_at(frame, layer, x, y, spesh_idx)
    elif y < self.height - 1:
        c,f,b,xf = self.get_tile_at(frame, layer, x, y+1)
        self.set_tile_at(frame, layer, x, y, c, f, b)
    elif y == self.height - 1:
        self.set_char_index_at(frame, layer, x, y, 0)