twist and lock blocks
Here is a slide show of a lesson where year 7 students explored twist and lock blocks and answered these questions (click to play):
In pairs How many different cuboids can you make? List them. Describe them. Draw them. What do you notice? Which one has the most squares on the outside? And the least? What can you say about what these shapes look like? Why? What other shapes can you make? Can you make a Tshape? Or a cross? Or steps? Can you make a shape with a hole in the middle? Can you make a shape with a hidden hole in the middle? Can you make a square (one layer thick)? How many 'rectangles' can you make? Join pairs into larger groups This is where the fun starts... put 2 (or more) together and answer the same questions. Can you make an 'interesting' cuboid where the two strips are twisted around each other. Make a puzzle like this and give it to another team! Continue to put groups together to make larger and more interesting cuboids. With 18 strips you will have 216 blocks... put them all together to make an interesting 6cube! 
