How do I move a hole randomly within a boundry

Hi Guys,

I have forum surfed this issue for hours now and I can't figure it out.
The issue is I have a box that a contains a hole, this hole must move randomly around inside the box (with duration 0) but can never return to the centre of the box (where it started). My Alice code looks like this atm (note: the distance from the centre of the box to each side of the box is 10m):

If hole distance to centre > 10
(stuck here, but I want it to move to a random spot in the box)

Else
hole move left random number minimum = -10 maximum = 10
hole move forward random number minimum = -10 maximum = 10

Any help would be greatly apperciated!

[x2495iiii]

Make four number variables, leftVar, rightVar, upVar, and downVar

Place four squares with their against each edge of the box, making sure to keep the square's centers touching the bottom of the box.

Then you'd need a complex method that might looks something like this:

rightVar set value to circle dist from right square - circle's width

leftVar set value to circle dist from left square - circle's width

(etc. for the other two variables)

Loop infinity times:
circle move right [random number [min = -leftVar] [max = rightVar] [integerOnly = false]] meters
circle move up [random number [min = -downVar] [max = upVar] [integerOnly = false]] meters


That should do it.

Thanks for the reply,

I tried to do what you said as best I could but it didn't seem to work - I have posted a link to a screenshot of the code but to help ill do a diagram too:

nwPost.........................................neP ost



.......................centre..................... .....



swPost.........................................seP ost

the hole has to move around but not go outside the box outlined by the posts.

here is the link: http://yfrog.com/20screenshot20100508at103p

Cheers.