The Starting position of a layer.
A layer occupies a portion of a column. The LOWER value is a percentage value such that the lowest part
of a layer will be at that percentage from the bottom. Example, if LOWER is 35 (i.e. 35%) and the Column has
a height of 200 (units?), the layer will begin at 70 (units) from the bottom (70 is 35% of 200).
double UPPER
The Ending position of a layer.
A layer occupies a portion of a column. The UPPER value is a percentage value such that the highest part
of a layer will be at that percentage from the bottom. Example, if UPPER is 65 (i.e. 65%) and the Column has
a height of 200 (units?), the layer will begin at 130 (units) from the bottom (130 is 65% of 200).