You can just use a palette. Try this: v := RTView new. v when: TRMouseClick do: [ :event | v clean ]. v when: TRMouseMove do: [ :event | e := (RTBox new color: ((ColorPalette qualitative colors: 9 scheme:'Pastel1') atRandom alpha: 0.5); size: 20 atRandom + 5) element. e translateTo: event positionFromCamera. v add: e. v addAnimation: (RTAccelerationMove to: event positionFromCamera + ((150 atRandom - 75) @ (150 atRandom - 75)) during: 5 on: e) ]. v -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.