Originally Posted by candi
Here is a chart for reducing/enlarging patterns:
http://www.thequiltedsnail.com/scale.html
For your blocks, yes, just enlarge on a photcopier by 200%. As long as when you measure the block on the paper it measure 12.5, you are good to go for PP.
Make sure to photocopy ALL of the pieces you need on the same photocopier as different machines can have slight differences in their sizing ratio.