Blek is a game that could only exist on a touchscreen.

It's intimate in a way that only a touch-based interface could handle, tasking you with working out the perfect repeating gesture to guide a black line to a series of coloured dots.

Precision is the aim of the game, but there's a free-form, exploratory nature to proceedings that makes experimentation and improvisation key elements in the time you'll spend with the game.

Anyone can have a go at solving the 60 puzzles that make up the game, and no two people need to come up with the same solution for all of them.

Dots

You draw a squiggle onto the screen and it comes to life, repeating itself over and over until it's collected all the coloured dots, wandered off the screen, or hit one of the black dots that you need to avoid.

The puzzles start off sedate and simple, solvable with a straight line or an expansive scrawl. Then come the grids, which you can solve with a little effort, or, if you'd prefer, conquer with a lot. The game begins to steal your space, pushing you towards more creative doodles.

I managed to complete one of the first chunk of puzzles with part of my signature, but the later ones require a more methodical, measured approach. There's still a creative aspect, but you need to put more thought into your gestures if you want to succeed.

It's here that the game comes a little undone. There are some levels that are razor edged difficulty spikes, and the creative momentum you've built up gets sucked away and replaced with some teeth gnashing and frustrated gurning.

Blek and blue

When Blek is at its finest it's a wonderful experience. It's free-flowing and smooth, and exactly the sort of game you could use to introduce someone who's never picked up an iPad to the joys of touchscreen gaming.

It's a shame that those soaring moments are dragged down a little by the tougher levels, but there's still enough here to make Blek one of the most intriguing puzzlers on the App Store.