I have a drawing (created by AutoCAD) given to me in which some block instances appear to have different characteristics to the block definition. For example, say I have a block called "Arrow". If I add an instance of the block to the drawing with 0 rotation, and with (1, 1, 1) scaling along the X-, Y- and Z-axes, then the arrow represented by the block points along the +ve X-axis.

However, I have some instances of this block in the drawing that point along the -ve X-axis. Now, I could understand that if those block instances have 180 degree rotation, or a -1 X-axis scaling, for example, but they have the exact same rotation and scaling properties as other instances that point along the +ve X-axis. How is this possible?

I've exported the drawing in DXF format, and looked at the definitions of two INSERT elements of the same block that have the same properties but that point in different directions - and can't tell any differences between them. And yet, when DraftSight reads in the file (whether in DWG or DXF format) it always displays the same block instances in the same way - it's not like the arrows occasionally switch directions. This leads me to conclude that there is some information embedded elsewhere in the drawing that tells DraftSight to render the different blocks instances in different ways, but I have no idea how it's doing so.

Can anyone explain what I'm missing and how this behavior is possible?

UPDATE: I've attached a file (Orientation.dwg) that has two Array instances. Both have 0 rotation and have (1, 1, 1) scaling along each axis - and yet they point in opposite directions.