Double Exposure or Strobist Tech?

[zeddified]

Spotted this on Petapixel:


Fancy double exposure or strobist technique?



Is it even possible for a strobist technique to produce this given that:

• Technically, you can only shoot from one side of the window/glass surface, because there is a city, and presumably, only air on the other side.
• Does critical angle re: reflection of light apply here?
• (Considering the above) Can you shoot a baby pressed up against the glass light this using strobes?

Just thinking out loud ._.