Depends on the overlap and the length of the original ladders. Assuming you are about 6' tall you should be able to reach up about 7'6" to push up the second laddder by hand. So if you have two 5m ladders you can achieve the combined length without pulleys. Hmmm...then again you need a slope for safety so you need a longer reach than that :-(
For shorter ladder lengths without pulleys you have to either use a 'pushing device' such as a piece of wood to extend the ladder when it is upright, or extend it on the ground first (which will then require a lot of space and muscle to get it upright).
Builders who have no fear stand on the lower bit, lean back a bit then extend the upper bit in jerks up the wall. Not my idea of fun. Not recommended for obvious reasons.
To decorate the front of a house I would recommend hiring a scaffolding tower - much easier and safer to work from :-)
Cheers Dave R