ALK is described as 'DAW that combines a sequencer and looper into a live tool that's as advanced as a traditional sequencer, letting you draw, move, copy and paste musical arrangements as well as layering live sounds' and is a Music Production App in the Audio & Music category. There are more than 10 alternatives to ALK for a variety of platforms, including Mac, iPad, iPhone, Windows and Linux. The best alternative is Giada, which is both free and Open Source. Other great apps like ALK are Luppp (Free, Open Source), Sooperlooper (Free, Open Source), Mobius (Free) and Loopy (Paid).
WoodStepper is a sequencer/sampler having both audio and midi out. The audio input sources can be the track audio, sampled audio or the built-in VCO. It consists of 4 independent 8-steps sequencers which can be linked to a 16, 24 or 32 steps sequencer.