I enjoyed this blog post and Javascript implementation of an interactive Quantum circuit inspector. http://strilanc.com/quantum/2014/03/07/Building-your-own-Qu

I enjoyed this blog post and Javascript implementation of an interactive Quantum circuit inspector. http://strilanc.com/quantum/2014/03/07/Building-your-own-Quantum-Fourier-Transform.html http://strilanc.com/quantum/2014/03/07/Building-your-own-Qua... It is a lower level than the Google project and only suitable for 3 qbits circuits, but I found it very useful for building up an intuition about the basic logic gates.