From the kitchen of: Marsha Truesdale, New London, Wisconsin
Over medium heat, cook sugar, vinegar and corn syrup, stirring constantly until sugar dissolves. Continue heating without stirring until mixture reaches 300 degrees on candy thermometer. Remove from heat and immediately stir in soda. Stir quickly and thoroughly. Pour into ungreased 8 x 8-inch pan. (Do not spread--it will spread by itself.) Allow to cool.
Melt chocolate in a small saucepan over low heat. Break candy into pieces and dip in chocolate. Put pieces on wax paper until coating hardens. Store in covered container.