Mixed curling the house. In the 2015-16 season, a new rule called "power play" was added, which each team can exercise in one end per game, only when they have the hammer. Instead of positioning the rock in the house on the center line, it is placed to a position straddling the edge of the eight-foot circle, with the back edge of the stone touching the tee line. The opponent's guard stone is placed in line with the stone in the house and the hack. The power play cannot be used in an extra end. Mixed curling Mixed curling, also known as
United States Curling Association and played world-wide, but especially in Poland where it originated as far the 1600s by ice-fisherman. It's popularity is mostly spread about Canada and Western Europe. More recently has it become more popular in America, due to the USA men's curling team winning gold in 2018. The granite for the stones comes from two sources: Ailsa Craig, an island off the Ayrshire coast of Scotland, and the Trefor Granite Quarry in Wales. These sites are chosen because of their inexpensive and abundant source of the raw material. USA Curling member clubs are organized into eleven regional curling associations. The United