This is the Analemma in the Cosmic Room, formed by the marks of the sun at several dates of the year, since the summer equinox, at the right of the analemma, to the winter equinox, at the left of the analemma, where the sunmark is close. But, where this mark comes from?, From this hole ...

 

You see the mark on the floor?, it comes from the hole in the ceiling, which is almost directly above the mark, why is the mark in different position than the preceding one?, because the picture was taken in different day of the year, this photo was taken in summer,near the summer solstice.

 

 

 The hole where the sunbeam comes trough is in the first you see in the roof, at the right. 

 

 

This is the mark minutes before the "marks hour", in the case of my Cosmic Room is at 12:45, this photo was taken on one zenithal day (there are two in any tropical zone, this is why is a tropical zone). Note the sun beam will fall perpendicularly from the hole in the ceiling, sun, hole, mark, earth center. If you are reading this (in english) is very probably you cannot make this mark in your latitud, because zenithal days is an exclusive issue for the ones who are between the tropics.