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AtomMorph demo
- objects>Demo>BouncingAtoms
- blue-click>open explorer
- select some submorphs>AtomMorph and inspect it
- self color: Color red
- self velocity: 0@0
- drag out the red AtomMorph
- make it larger
- copy it
- inspect it
- self velocity: 2@3
- drag it back to the BouncingAtomsMorph
- click on the red Menu handle and embed it
- self browse the AtomMorph
- browse #bounceIn:
- modify to beep after bounce:
bounced ifTrue: [self velocity: vx @ vy. Beeper beep ].
- very noisy, so add test for color red
	bounced ifTrue: [self velocity: vx @ vy.
		self color = Color red ifTrue: [Beeper beep] ].
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Alternative: <to try>
- create a subclass of AtomMorph with a different colour that beeps
- instantiate it and embed it ...
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