Open Ball.jpg and use the Elliptical Marquee tool to roughly select the ball. Nudge and Expand/Contract the selection to fit, then copy-and-paste it as a new layer and label it ‘Ball’. Position and scale it to fit within the central area. Although our photos were taken from the same distance, a certain amount of re-sizing is necessary.
Open Mouse_3.jpg, generate a path-based selection, copy-andpaste it into a new layer and flip it (Edit > Transform > Flip Horizontal). Position and re-size, and label it ‘Mouse circuit outer’.
Next open Mouse_4.jpg, drag and drop as a new layer (there’s no path), and label it ‘Mouse circuit inner’. Lower the opacity, then position and re-size it over your previous layer. Generate an inverted selection from the underlying layer, ensure your new layer is targeted and erase only the lower inner and outer areas – don’t worry about the cable yet.
Follow the supplied paths to paste new layers into your working document from Mouse_5.jpg (labelling it ‘Mouse top inner’) and Mouse_6.jpg (labelling it ‘Mouse top outer’). When you’re happy with the positioning of all your layers, generate a selection from your uppermost layer and create a new Alpha Channel filling the active selection with white. Next paint out the wheel slot using a white, hard-edged paintbrush, then hit Cmd/Ctrl + I to invert the Channel.