Exodus 29:12

29:12 and take some of the blood of the bull and put it on the horns of the altar with your finger; all the rest of the blood you are to pour out at the base of the altar.

Exodus 30:2

30:2 Its length is to be a foot and a half and its width a foot and a half; it will be square. Its height is to be three feet, with its horns of one piece with it.

Exodus 37:25

The Making of the Altar of Incense

37:25 He made the incense altar of acacia wood. Its length was a foot and a half and its width a foot and a half – a square – and its height was three feet. Its horns were of one piece with it.