They're used by Mps to hail their local football team for a cup victory, to roar their condemnation of anything that's upset them and to sound off about any subject, sublime to ridiculous, under the sun.
One MP has even used the device to place on the record his congratulations to himself for giving up smoking.
We're talking about the Early Day Motion-- motions which are hardly ever debated but which do allow Mps to vent opinions and test how much support
there might be for their favourite causes.
Is there any serious point to them? Should more of them get debated?
Those are questions now being asked by a committee of MPs.
David Wilby reports on the uses and abuses of parliamentary graffiti.