list of vehicle types from most to least varied
| tank | car | mech |
| bicycle | ||
| boat | spaceship | |
| plane | ||
| helicopters | ||
tanks and cars are subject to the concept of gravity and air drag but other than that they are very flexible
mechs usually attend to the same concepts as tanks and cars except they're bipedal so they can approach sudden shifts in vertical terrain
bicycles whether they are motorized or personally propelled are similar to cars with increased obvious emphasis on weight distribution
boats must be buoyant in water even if they can dive underwater which introduces several new concepts of physics and decreases the variety of design
spaceships are not significantly constrained by physics so designs might be strange but it would ultimately lead to stagnation where you can just make a solid cube fly through space
planes are the second least varied machines with numerous concepts affecting lift off and then staying in the air afterwards
helicopters are the least interesting designs as a combination of planes restricted with vertical lift propulsion