I think the original photo shows smaller blocks...even 1.5" strips would give you an 8" block, so piecing this to make, say, a 6" block would be pretty challenging...you would be working with 1" strips.
I cut a 1" strip and a 1.5" strip off every fabric I buy, so have bins of strips all ready to go for a scrappy heart.
Agreed on the mystery! Making up the sub-blocks you would never suspect a scrappy heart was en route!