Optical Illusion- Checkered Line

Another 4th grade Optical Illusion!  This one was inspired by an artwork I found on Etsy.  I had the kids create a grid.  In each box they placed a large shape and in each of those shapes, a second smaller shape.  They drew a line from one side to the other going through each shapes.  Sometimes they had to introduce a second or third line.  They then checker boarded the design. This one was really successful.  I will do it again!