Demonstrating tenses and aspect

Blimey, it's been while since I posted. Have been kept busy with a) a British Council Inspection, followed very closely by b) an OFSTED inspection, both of which officially deemed EFL and ESOL to 'Kick Arse', of course.
I was reading a blog post yesterday, via Twitter, of one teacher's attempt at explaining tenses and the relationship of tense forms to notions of reality and unreality. Unfortunately, I forgot to bookmark the site, and I've forgotten who wrote it! (UPDATE: Found it! It was Sandy Millin, over here - thanks, David!)
She mentioned how much Michael Lewis, in The English Verb (1986) influenced her teaching, and I'd certainly agree - it's an informative, useful and thoroughly readable book, and one that formed part of the background reading for my 2007 conference presentation on Tense and the concept of Distance.
One part that was particularly useful was Lewis' timelines, explaining the relationship between simple, perfect and going to, but one day while using these timelines in class, I realised he'd missed a simple, but beautifully efficient trick for teaching aspect to learners.
Here it is.
Start by drawing a street corner on the whiteboard. put a stick man on the corner. Ask the learners where the man is, then ask them what tense they are using (He IS on the corner). Next, draw some traffic going past. Ask the students what the traffic is doing (it is passing the man, for e.g.), then ask them what tense that is. Draw a shop to the right: Tell them the man is going to the shop and ask what he's going to buy (e.g. he is going to buy a banana). Now draw a house to the left: Tell the learners that this is the man's home and ask them where he has come from (e.g. he has come from home) and again, elicit the name of the tense. You should end up with a board that looks like this:

Now we have the street corner, point out the directions the man has to look to 'see' the tenses. After that, take away the extraneous details and draw this:

This looks much more like Lewis' timelines, except with a crucial distinction. In The English Verb, Lewis makes the vertical line represent the simple tense: in mine, the vertical represents the point around which the continuous occurs, with the intersection of the lines (the 'street corner') actually representing the time. That is, the directions moving away from the intersection demonstrate the fact that English tenses are, in reality, aspectual (with the exception of the present and past simple tenses).

Having done this and drilled the tenses, move the action back to yesterday and ask the students where the man was. They should, fairly naturally, then come up with the other tenses. Repeat for the future, then draw this:

And there we have it. I've used this for several years now, and it helps the learners understand that there is a spatial element to the tense system in English. Of course, you will have noticed that the perfect continuous forms are not included on this: I've done that for the sake of visual simplicity, but they can be added - preferably during a different lesson :) 

Feel free to use these pictures, but I would appreciate an acknowledgement, please!

What do you think? Ideas for improvement and criticism gratefully received!