By clicking on the "change cut" link, you can go for the traditional approach pictured below (240 piece classic) Be warned averages completion time is over 71 minutes. Or you can make it easy for yourself (like I did) with the 12 piece.
If you want to go international there's a US state version
Or try the rather freaky 91 piece lizard version which apparently has an average completion time of 24 minutes.
I should say thanks to Jon J for bringing this to my attention although it's a maddening time waster. It's worth having a go at it in good time though in case TfL's lawyers find some way of taking it off the interweb. Have errr... fun.