Reference: pmTiles

pmTiles(pm, N), where pm is a pixmap and N a positive integer, returns a pixmap, no smaller than pm, consisting of a rectangular grid of N×N rectangular tiles of pm, in a random order, such that each point in pm is represented in the result in exactly one tile.

pmTiles(pm, Nx, Ny) creates a tiled picture of Nx rows and Ny columns.

pmTiles(pm, Nx, Ny, dx) creates a tiled picture of Nx rows and Ny columns. dx is the spacing between tiles, both vertically and horizontally.

pmTiles(pm, Nx, Ny, dx, c) creates a tiled picture of Nx rows and Ny columns. dx is the spacing between tiles, both vertically and horizontally. c is the colour of the spacing.

By default, dx = 2 and c = rgb(1, 1, 1) (white). Notice that, when N = Nx = Ny = 1, this function can be used to create a solid-colour frame around pm.