I came across the following Facebook post claiming that these artifacts are examples of ancient kettlebells

http://i.imgur.com/S4xy7Ns.jpg

This seemed like a dubious claim to me so I set about trying to get information about what they actually are and what they were used for, but didn't have a whole lot of luck. Based on my googling, the top two look to be Jiroft Stones which were apparently used for some kind of ceremonial purpose but I couldn't find any specifics. The bottom right is obviously a modern kettlebell so we can discount that, but what are the other three? Where are they from and what were they used for? Are they some kind of ancient exercise equipment like Facebook says or something else?