I just typed this up for our Jan/Feb thread so thought I'd add it here as well.
To make a number 1 shaped cake, cook cake in a large rectangle cake tin (I doubled the recipe). Wait until it's totally cooled before you cut and ice.
1. Cut the rectangle in half length ways, so you have 2 looongg rectangles
2. Leave one of them whole. This will be the upright part of the #1.
3. Cut 1/3 off the other loooonnng rectangle. This little piece will be a square. Cut it in half diagonally, so you have 2 triangles.
4. One triangle forms the top left hand part of the #1.
5. The remaining two-thirds of that loooong rectangle is the bottom of the #1.
6. In the instructions I read, it said to eat the second triangle (lol) but I added it to the bottom of the one (cut it and arranged it so it was a little rectangle) so it was longer, cos I thought it looked better. I pieced it together with icing.