We study a generalization of sturmian sequences by constructing a “stepped surface”, given by a plane approximation with three kinds of square faces oriented according to the three coordinate planes. With a projection operation, we build a tiling of the plane by three kinds of diamonds. We define in this tiling a complexity function by counting the number of patterns in a given height window. We give the explicit form of this function in the case of triangular windows and parallelogram windows.