 Now that we've discovered arrays, it would be nice to be able to create them. J gives us the operator's shape and integers to create arrays without having to type out each item. Integers is a two-character operator used to create a list of integers from 0 to 1 less than the integer argument. Once we have created the list using integers, we can manipulate it just like we would any other list. We could make it into a list of natural numbers by adding 1 to the list. We can calculate the successive powers of a given base or the successive roots. Notice that the brackets are used here to ensure the list is created before the root calculation is done. Without the brackets, J would first take the square root of 7, 2.64575, which would result in a domain error since integers expects an integer argument. When shape is used to create arrays, it takes two arguments. The left is the shape of the array we wish to create and the right is the list of items that make up that array. This provides a way to create arrays of multiple dimensions and lets us use higher dimensional arrays as arguments. Here we assign our array to the variable X using the assignment operator. Now we multiply the corresponding numbers of the two-dimensional matrices, which gives us the results. Note that this is not matrix multiplication, but rather multiplication between the corresponding numbers that the matrix contains. Before you go on, try to create some of your own matrices using shape and integers and perform operations on them. The J interactive session excels in providing opportunities to learn through exploration.