The Card Trick Quilt Block is another prime example of a quilt block that appears complicated to make but is actually quite simple once you break it down into its basic units. The visual illusion over overlapping "cards" is created with the clever use and placement of color.
Essentially the block is a 9-patch, as you can see in the exploded version of the block pictured below. Half-square triangles, Y-Units, and a central Quarter-Square Triangle unit work together to make this simple block look tricky.
Card Trick Quilt Blocks have a nice appeal also when grouped together in straight sets: