When I have nothing better to do, I love killing a few minutes with music maker apps such as Melodica or Band on my iPod touch. From the looks of it, I might have to add Looptastic to the arsenal.

We wrote about startup A Vinyl Bar in Shibuya in April when it launched its Bop “pocket DJ” app. The company was founded by former Spotify exec Máuhan M. Zonoozy as “a label that treats software like ...