This is a modular riser system for Bench Cookies. It can be customized for height and fit in the dog hole. The four lobed design also works in square dog holes.
You'll need additional hardware to use these. For the standard 1 cookie height risers you'll need 1-1/2", 2-1/2", and 3-1/2" 5/16-18 bolts and regular and fender 5/16" washers.
The lobes of the risers are created using Manticorp's Archimedial Spiral Module.