It’s a dough baller! Click this link to see a manufacturer’s video of a similar machine at work.
We use this piece of equipment every morning in the MCL Restaurant & Bakery kitchens to make our signature Cloverleaf Rolls. The baker mixes and kneads the dough just like you would at home. Then he or she puts the dough on a special plate. It starts out as one large blob of dough and ends up as several golf ball sized pieces. This happens by putting the plate, which has special indentations, into the machine. The machine shakes and individual rounds form in the indentations on the plate.
The baker puts three balls together in each well of a muffin pan. As the dough rises, it clusters together to form the cloverleaf shape. I doubt you’ll want to purchase your own dough baller for home, but you can roll them by hand and use the same technique to create your own homemade cloverleaf rolls.