The back is pieced.Sorry about the picture, there hasn't been too much opportunity for me to photograph in daylight being at work, and its not really as creased as it looks, I just didn't lay it out very well.
Anyhow you get the idea and as you can see I've just gone for something really simple. I gathered up some of the offcuts of red fabrics left from cutting the pieces for the front, matched up strips in 3 different widths and then just pieced them together in 3 long strips.
Next it's the bit I don't enjoy so much, basting the layers and quilting. I can never seem to get things quite right and always end up with a few puckers on the back, but hey I've only so far completed 3 quilts in my life and practise makes perfect so I'll just keep going and hopefully one day I'll get better :)
For any rainbow challengers reading this, don't worry I still have plenty more red scraps left for use in future months :)