wrench events. make a certain trail of bricks . Set all bricks you want to climb with these events:
Name: climbbricks
'onactivate named brick climbbricks setcolor white'
'Delay: 500 onacivate named brick climbbricks set color 'original color here'
'onactivate player addveolcity [] [] [10]'
So all climbable bricks will flash white for half a second, and when you rapidly click them, they will make you go up.