In 1977, Ammann  described a set of six tiles later called the set A1 by Grünbaum and Shephard . In order to ensure an aperiodic tiling, the edges of the basically square tiles have tabs and indentations. The tilling is similar to the Robinson tiling, but shows features of independent interest.
Checking the "decoration" button shows a pattern of interleaved H symbols.
The method of presentation and parts of the code in this Demonstration are adopted from Robinson Tiling.