As the inner-section of the tower fills with magma, the only ways to escape are the holes in the roof of the tower. The intent is that the tower must be evenly filled with magma before any will spill onto the ground below, ensuring an even distribution of magma to all points where holes are present in the roof.
The tower doesn't work as intended.
Severedcoils
Submitted by: Dorten - 2010-03-01
Learn the laws of DF physics!
Output holes should be on the exact same distance (path-wise) from screw pump.
Submitted by: Fire Imp - 2010-03-07
Nothing ever works as intended.