Exodus 27:2

27:2 You are to make its four horns on its four corners; its horns will be part of it, and you are to overlay it with bronze.

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 38:2

38:2 He made its horns on its four corners; its horns were part of it, and he overlaid it with bronze.