Colour Book

Colour Book opens on a wooden desk with a cream sheet in the middle, a tray of paint pots along the bottom and a box of crayons at the edge. Thirty-one pages are drawn in clean black line art — cats, foxes and owls, a rocket and a steam train, a castle and a treehouse, cake and pizza, three mandalas and a kaleidoscope, a dragon, a unicorn, a mermaid and a robot, a snowman and a field of pumpkins. Every shape on a page is a region of its own, so a tap fills one area and only that area. Tap a line by mistake and the nearest region takes the colour instead, which is what makes it work with a fingertip.

There are four ways to lay colour down. Flat is the plain pot. Glitter scatters sparkles that drift into place and keep catching the light. Gradient blends two colours, and dragging across a shape sets which way the blend runs. Pattern fills with dots, stripes or checks. The crayon scribbles freehand but stays inside the shape you started in, so you can shade a petal without touching the one beside it. The rubber puts a shape back to white, the dropper picks a colour straight off the page, and undo and redo go back thirty steps.

The tray holds thirty-six standing colours plus the eight the page suggests, and a mixer with a hue ring for anything else — mix a colour and keep it in the tray. Pinch to zoom in on the fiddly bits and slide the page with two fingers. Colour every region and a sticker is stamped on the page, the page joins your gallery, and you can save it as a PNG. Everything you colour is kept in your browser, so a half-finished dragon is still half finished tomorrow. Works with a finger, a mouse or the keyboard, and nothing to download.