These rectangle sets consist of various combinations of the basic rectangles found in all sets. Our customers tend to start out with smaller sets about the time their child is 3-4 and then add to it over time. These Rectangle Booster Sets allow you to enlarge the supply of the basic blocks that get used the most. This can also be accomplished by using the individual blocks pages to buy exactly what you want, but the booster sets carry a discount and the individual blocks do not. These are just right for the never ending quest to build the world's tallest tower.