If you like Paper and want another sketch app for the iPad that looks and acts like Paper but with a slightly different set of tools, check out Tayasui Sketches. The app offers an impressive assortment of drawing tools for free, and the in-app Pro Mode upgrade, at a reasonable $1.99, is cheaper than any of the upgrades Paper offers.
Launch Tayasui Sketches and you'll be greeted with a blank canvas and nine drawing tools, plus an eraser and a color strip for selecting a color for your brush or pen. Like Paper, Tayasui Sketches is not cluttered with menus and buttons. A few, simple gestures is all you need to know to navigate the app.
Swiping left and right with two fingers acts as undo and redo commands, respectively (and in settings, you can flip a switch to add small, unobtrusive Undo and Redo buttons in the upper-right corner instead). You can swipe to hide and show the tools, and you can double-tap the eraser to erase all marks on a canvas to start over.
You can pinch out to zoom in on a sketch, then you can use two fingers to hold and swipe to move about your canvas. Pinching in shrinks your current canvas to either of two thumbnail sizes, which you can then swipe to browse through your various works.
Unlike Paper, you cannot save groups of sketches into notebooks. Tayasui, which is Japanese for "easy and simple," embraces a flat hierarchy, which is really no hierarchy at all. When viewing the larger of the two thumbnail sizes of your sketches, swipe up with one finger to view the sharing options. The four sharing options -- Facebook, e-mail, save to library, and Twitter -- are listed as stamps, which you affix to the open envelope before swiping up again to share.
When you're in the same large-thumbnail view, you can swipe down with one finger to send a canvas to the trash, while swiping to the left with two fingers creates a copy of a canvas.
Pro Mode adds more tools and brush sizes, a pro brush editor that lets you make fine tweaks via slider to the brush size and opacity, and a color eyedropper that lets you add new colors to your palette. You can try out the Pro Mode upgrade for one hour before deciding on whether you want to plunk down $2 for it.