In a darkened gallery, four white fabric panels are suspended from the ceiling, stopping midway to the floor to form a large square that the viewer can enter.
I have imagined my father composing this letter in his head, reciting it in a whisper as he paced the "concrete room" during those precious, silent hours between midnight and early morning when the loudspeaker in the centre of the ceiling stopped its relentless blaring out of revolutionary songs and speeches.
For some of his members, the "walkaway value" in any negotiations was basically no deal at all, because they had promised to never vote to raise the debt ceiling, period, full stop, or to vote for any deal that funded Obamacare.
"Only last week ministers criticised the 'grey ceiling' which stops people working beyond the age of 65," said Lishman.
One of the most striking works is a bound staircase at the far end of the room that ascends all the way up to the ceiling then stops.
A number cited problems striking a work-life balance, and others said there was a glass ceiling that stops them reaching senior positions.
For example, even though women have been flooding into the labour market in growing numbers in the past few decades, the "glass ceiling" that stops them getting to the top mostly remains in place.
When the federal government hits its debt ceiling, borrowing stops, but deficit spending can keep right on going for a while, using what the Treasury calls "extraordinary measures". What extraordinary measures really mean is the federal government takes money out of other accounts (such as employee retirement accounts) to cover its overdrafts until the debt ceiling is raised.
President Obama on Tuesday formally opposed the latest House Republican bill to address the debt ceiling, but stopped just short of promising to veto the legislation if it reaches his desk in the next week.
"UN forecasts of 1980 predicted it was going to bump into a ceiling and stop increasing next week, but it didn't happen; [it] carried on increasing pretty much as before".
