After much thought and speculation it gradually dawned on me that 42 is a kind of opposite to 36. 360 is a reasonable number for 12 months à 30 days (as the Egyptians once had it) or for 24 half-months à 15 days (which maybe could have been used by some rongorongo writers). The course of the sun with 6 double-months (à 60 days) could have been another view:

 

6 'flames' was an easy and beautiful form and if each one had 60 days, the total measured 360 days.

 

420 I at last found out, is the '7th flame of the sun' (so to say), i.e. what we get if we add an extra flame: 360 + 60 = 420. Conceptually this is equal to an invisible (hidden) flame, a flame which exceeds the full cycle.

 

In mythic thought, when you pass beyond the full cycle you pass into the 'beyond', i.e. the Underworld.