I'd like to ask about where you point out by the following expression.
1) There is a red building at the corner.
2) There is a red building on the corner.
3) There is a red building in the corner.
The corner must mean the point where two roads meet. So I cannot get the difference of the sentence 1)2) 3).
Would you give me some guidance?
"at" refers to the general location of a point in time or space.
EX: I am at the bank. Am I inside the bank or outside the bank? No one knows. I am "at" a general location, the bank. I could be either inside or outside the bank.
EX: Both the big hand and the little hand are at the 5. It's 5 o'clock. I'll see you at 5 o'clock.
"on" is short for "on the surface of".
EX: The bank is [situated or located] on the corner of 5th and 7th.
EX: It's cold. Put the hat on your head.
"in" is short for "inside".
EX: I am in[side] the bank.
EX: The chair is in[side] the area where th two walls meet. It's in the corner.
Note, "The bank is in the corner" is used when referring to a map or , say, a small toy building,
Sam: Where is the bank?
Max: In the corner (of the map).
Sam: Where is the miniture toy bank? I want to add it to my train set-up.
Max: It's there, in the corner (of the room).