The template for the IH25 system is any pentagon having two equal parallel sides and another two sides equal and adjacent to one another. All five sides can be shaped as indicated  by the half-arrows. The template and any tile shape formed from it have no internal symmetry, as indicated by the dog pattern.

A translation cluster is

A section of the tiling formed by this template is shown below, with a translation cluster outlined.  The two basic translations are indicated by  the vectors drawn from the highlighted cluster. The tiling has two different centres of two-fold rotation symmetry, and two different axes of glide reflection symmetry; an example of each is shown. The  symmetry group of the tiling is pgg.

As an example, a shaped tile which, with decoration, can be made to look like an animal's head  

 Four different colours are required in the tiles to avoid tiles of the same colour being adjacent to one another.

 Author - Tom P McLean --- tom.mclean@virgin.net