The line between “math manipulative” and “toy” in our house is very blurry–actually, I don’t think it’s there at all. We have a variety of math manipulatives, and all of them get played with as toys. And of course, toys can make great tools for learning math! Jumping Spider built this elaborate pattern block creation yesterday afternoon. And Honeybee pointed out to me the four different types of rhombuses: orange squares, blue diamonds, and tan diamonds.
If you want to do more math-oriented activities with the pattern blocks, I have used the book Pattern Block Activities to introduce different concepts.