You did indeed.
Conversely, the relief could also be a literal depiction of the Heliopolitan creation myth.
The presence of Atum in a crypt - which is where the alleged 'light bulb' can be viewed - is hardly surprising. He appears in serpentine form at the beginning AND the end of the creative cycle. The crypt houses the corporeal body - the first human life was thought by AEs to have been created by Atum and from the Old Kingdom period onwards, it was believed that Atum lifted the soul of the deceased to the heavens.
An appropriate relief for a crypt, then.
It is for these reasons that I believe the relief is a literal depiction of the creation myth and that the serpent in the bubble is Atum, supported by the arms of Nut.
The other 'theory' remains unconvincing, to me at least.