I have a theory to prove the world is flat. It involves placing wooden school rulers end to end around the circumference of the world. How could the world possibly be curved if the rulers are all straight?
A further conspiracy. All our rulers are lying, they are all individually curved due to the Earth's gravitational field. Is the education system broken?
This must mean the only way you can measure a true straight line is in space. I propose we launch a space rocket with an construction expert on board to make a brick, this brick will be perfectly measured by a wooden ruler made with a tree grown in a special lab with tree experts on the ship. The brick will then be measured with the original wooden ruler created to measure it to test if the brick and ruler are straight.
Finally, due to the lack of gravity, humanity would of measured the only true straight line, a spirit level wouldn't work, because the bubble of air would just float, even the spirit level is biased against Earth's gravity.
I feel an adventurement coming on.