Here is a concept of SpaceX's early 
Mars Base Alpha by Twitter user 
Sotiris. The concept features a pair of crew 
Starships with 
Falcon 9 style landing legs, several pressurized Mars Cybertrucks, 
The Boring Company's tunnel boring machine and 3-level 
habitation modules derived from used Starship propellant tanks and connected in pairs (a questionable idea, we think).
 
 
Cutaway of the habitation module:
