Initial proposal at C&A Meeting: http://www.slac.stanford.edu/exp/glast/ground/LATSoft/vol1/geometry/notes/GeoApril2007.pdf See Slide 7
When Joanne modeled the tiles as depicted without changing anything else Joanne realized there would be a gap along the edge where the sides come together for rows 1 and 3 so she modified the design by making the width of these rows greater. You can see some more pictures at http://www.slac.stanford.edu/exp/glast/ground/LATSoft/geometry/pictures/ACD/newSides/
From Alex, for our information, in reality the corner gaps between the adjacent sides tiles are 4mm in nominal.
Checking Changes
Ran detCheck's dumpIds application to compare the output using xmlGeoDbs v1r39 against v1r40 (contains changes for side tile shingling). The initial output provides a count of materials, constants and detectors - the only difference between that portion of the output is in the number of constants. It is now 771 rather than 753.
Next up: Modifying side ribbons to follow contours of new side tiles.