public CompoundShape GetFlatShape()
{
var result = new CompoundShape ();
var pos = TileSizeYVector / 2f;
result.AddTriangle (pos + TileSizeXVector / 2f, pos - TileSizeXVector / 2f, pos - TileSizeYVector / 2f);
result.AddRectangle (pos - TileSizeXVector / 2f, pos + TileSizeXVector / 2f + TileSizeZVector);
pos += TileSizeZVector;
result.AddTriangle (pos - TileSizeXVector / 2f, pos + TileSizeXVector / 2f, pos + TileSizeYVector / 2f);
return result;
}