Sketchbook Challenge

I am challenging myself to fill a 100 page sketchbook with all doodles using BIC ultra thin permanent markers.  I love them!  I got a pack of 36 (I think) at Staples for about $20.  I have done about 70 pages and several of the markers have finally run out.  I replaced a few last week including the black (which I have replaced several times).  Obviously I use that one a lot!


I also found a Sketchbook Challenge blog HERE.  They have monthly themes for you to follow.  April's theme is open: as in flowers, doors, hands, whatever else you can open...your eyes.  So here are the pages that fit in the topic.

I am thinking about making some of them into greeting cards.  Any suggestions as to a site to use for that?