Very nice artwork collection, there. That would make some really nice garden art, especially if your garden was huge! There's a farmer near where my parents live that does something similar with farm equipment, and won an award for it. The entrance to his farm's driveway is guarded by a metal serpent-like dragon!
The bull reminds me of these bilboards they used to have all over southern Spain. They were to advertise some kind of alcohol, but weren't allowed to put the name, so they're just huge silhouettes of bulls.
Oh very clever of those Spaniards! lol. I think that kind of art made from so many items is just amazing they way they make it look so good.