4x4x4 Led Cube - AVR doing Bit Angle Modulation / Single PCB base

Before starting 8x8x8 Cubes or RGB Cubes it would be wise to excercise with a simple 4x4x4 cube. The advantage is that such a cube can be driven by a simple Atmega microcontroller (and some fets). Also, the spacing for a 4x4x4 cube allows the whole to be placed on a single 10x10cm PCB. To keep things simple, I decided to also use the PCB as a baseplate by soldering the components on the 'wrong side', even though most are through-hole components. Normally I would use SMT, but it is impossible to route a single-layer board with SMT. It's been quite a puzzle to get al the routes done manually, since Eagle wouldn't understand one bit of what I was trying to accomplish.