There's a new Web App for that and it's free!

Type app.robinruthdesign.com into any desktop or mobile device browser (or click on the link below). No need to go to the App Store or Google Play as my old app is no longer supported there.

Design all of the Skinny Robin and Fat Robin blocks using the 87 colors of American Made Brand Solids by Clothworks.  Preview your blocks in thousands of combinations before committing them to fabric.  All the animated videos and video tutorials right at your fingertips. Use the Strips Calculator to figure out how wide and how many strips you will need for any size block in my system!