Key Stage 4. Additional material: A grid matrix can be represented in a 2-dimensional array. Write a program that allows the user to store a letter in such an array with 8 rows and 8 columns.

MATERIALS: – One full size mattress – One 4 x 4 grid Ikea Expedit bookshelf (find some inexpensive options here on craigslist) – 2 sheets of 1/2″ thick plywood cut to 38″ wide x 60 ...