so here are hacks for G4 iMac and a Intel.
... don't know exactly what model name this IKEA lamp is ...
Take the mounting plate & glue it to the iMac
I tried Velcro & double-side tape, but both are not strong enought.
Wrap some masking tape over the lamp arm before bending, so there won't be scratches.
Idealy, lamp should be flush with the framing.