Inverter

Not bad, got a slight variation for you. http://everycircuit.com/circuit/4901092418912256

Am I tripping? The ground is gone.

These EC logic trains can form circuits without the usual earth icon, as you can see. Personally I don't think it is a good idea to do without the usual earth because various volts and amp results will be different and can be very misleading. Here are two examples: 1) look at the V meter reading as seen, then put a usual earth in place and look at the new V reading ...very different. 2) put an amp meter somewhere eg between the lower right mosfet drain and the upper right mosfet source...see the different current reading with and without the usual earth....Such a difference can effect components...eg see how the top left mosfet gate bar does not come fully out....To get that bar fully out there would need to be less than 4.13v from the supply on the left at the moment. Now put the usual earth in place and you will see that the gate bar comes fully out at when the supply volts drops below the expected 4.57v (why the circuit was designed without gate considerations is another matter).

@BillyT...your gate bars likewise could activate fully if you were to alter your two top mosfet VTO settings to 1v (and assume that these mosfets are LL with that spec on their datasheet...some do have that), then drop the supply on the left down to 2.99v or less....but not too much less else other things may not work.

I can see why with the power supply floating around the room.