Compound Variables

• Arrays
  
  1. Arrays can be constructed by taking a number of simple variable visualisations, punching holes in them, and using metal fasteners to string them together. The picture is of three integers joined together. A post-it can be used to give a name to the array.
  2. Egg cartons make great arrays as well. This is a 1x5 array for Ada (one can use characters as index values), and this is a 2x5. German Überraschungseier (surprise eggs) are very useful as values, as they don't break and can be given away to the students as prizes for other things in class.

• Records
  Records consist of different types of variables collected under one name, so I use some boxes that I put holes in and pin to some more joughrt cups [preparing for teaching using these models requires eating about 5 liters of joughrt!]. I like to use Hexenmeister Fleckentferner boxes, as they have a little window that is nice for putting in the contents without having to open the box and destroy the static properties of the whole thing. This picture has a two integer and two string record