Arrow in arrow out.
And here is my latest 3D offering the rotating arrow. Well I always find that some students don't understand where the cross and point symbols come from when drawing field lines, now they'll know.I drew this in Sketchup (it took ages but I learnt a lot). If you use a smartboard with SMART notes 11 then you can paste the arrow into your notes. Next project is to make some examples of currents and fields.
If you want an arrow for your board you can download my 3D sketch, right click and save target here