CT-gui is a touch-friendly GUI toolkit which can be used on the Linux desktop and on Android devices. Development can be done quickly and easily on a Linux box, then ported to an Android tablet or phone. For graphics, only OpenGL or OpenGL ES is used. For audio, ALSA is used for Linux and OpenSL ES for Android. As you might expect, the Android SDK and NDK should be installed on your system. Two demo projects called CT-synth and CT-farfisa are included, which are a polyphonic synthesizer with about 20 built-in patches, and an organ with many sounds. These can be played using the mouse or your fingers, or with an attached MIDI keyboard.