Problem:

When designing contraptions involving pressure, ambient heat, etc., it is hard to judge the location of the 4x4 air simulation tiles without a known reference. The best way to find the location of these tiles is to place a wall and take note of the tiles it occupies. However, this is both annoying (interrupts building) and unnecessary.

Concept:

 TPT already has a grid (accessible by pressing the [G] key), but the grid only snaps to odd number spacing. This feature could be implemented simply by adding one more grid (4x4) to the rotation when pressing [G] .

Potential Implementation:

 On the 10th press of the [G] key, the grid will shift to 4x4 squares (instead of resetting the grid). The grey lines would, of course, need to be 2 squares thick to line up properly. 

Reasons to Implement:

•  Makes design of pressure/aheat contraptions easier
• Helps users to easily build structures aligned to ingame walls
• Provides more display options to the user

EnganK:

Grid 1 actually has an even spacing - three pixels inside the square and one on the border. Grid 1 is also already aligned to the air/wall grid, this is easy to check if you turn Grid 1 and pressure display on and pause to change the pressure with the tools.

Even though the spacing is even, it's still more awkward (to look at, at least) than just a 2px thick grid. It would still be nice if both existed.