A simple model of 1D structure based on a Fibonacci sequence with variable atomic spacings is proposed. The model allows for observation of the continuous transition between periodic and non-periodic diffraction patterns. The diffraction patterns are calculated analytically both using ``cut and project'' and ``average unit cell'' method, taking advantage of the physical space properties of the structure.

PACS numbers: 61.44.Br, 61.43.--j, 61.10.Dp