Drag and Drop - Constructing Proper Securement

Hello - 

I am having some trouble putting together a drag and drop interactive course showing proper securement of boxes on a trailer.

Attachment 'securementexample' shows the correct way to place the straps (red lines). Is there any way to have the user drag and drop the straps onto the empty trailer and Submit to see if they secured it correctly? The main idea is to have users secure the load themselves and to keep the straps out of the red shaded areas shown in 'securementexample2' attachement. 

I would love to hear your thoughts on how to construct this interactivity. I can't seem to think of a workable solution.