Square Pattern – The entire block is grid patterned. The problem with this design is that soft blocks create bigger indents, and don’t always satisfy ASTM E18-17e1 for the distance between the edge and another indent. You can use any other square to solve the issue.

Circle Pattern – The design solves the distance problem between indents, thereby meeting the standard. There are complaints of excessive space wastage. This, however, is the ASTM E18-17e1 rule.