A FREE phone app can show anyone absolute proof that we do not live on a ball earth but a flat earth. The THEODOLITE APP is calibrated for level and for verticle height whenever the user decides to “zero” or calibrate it. If we live on a ball, the application MUST show the difference in curve at any distance at a rate of 0.009 degrees per kilometer. What is level at a starting location MUST show almost 0.1 degree at 100 km distance from ANY starting point on earth. The APP does not “re-calibrate” – the phone does that. this is absolute proof we do not live on a ball. In this test, 200 miles or 3219 km distance was used. NO CURVE was shown. ANYONE can prove this for FREE.