The problems with e-learning concepts

I have been doing a bit of work in the e-learning filed again, and the age old problems have cropped up again: How do you illustrate something NOT happening? How do you portray a SERVICE or other non-pysical concept? How do you make buildings look like they are not floating in mid air?

To make something NOT happen, we used to just draw it happening, and put a "NO" sign through it, like the no parking sign, but without the P.

But yesterday I took a different approach - I drew it about to happen, then withdrew it. Worked quite well!

We hit these problems in SmartForce back in the day and now they are coming back to haunt me!