The grid and dots you see are from the formwork used to cast the concrete.
Formwork comes in 2 flavours, metal or wood. The grid is caused either by the size of form panel used or a strip of wood is screwed to the inside to cast the groove. The dots are from the metal tie rods used to hold the 2 sides of the form together and this is usually filled in after the forms are removed.
the other way this is achieved in the “real world” is that they are pre-cast panels that are assembled on-site. the hole are lifting eyes but more are added to the concrete slabs for decorative purposes if they are not being covered over.