Combine sugar,syrup and vinegar in a large deep saucepan over medium heat, stirring until sugar dissolves. Then continue cooking WITHOUT stirring until 300^ on candy thermometer. Remove quickly and stir in soda(it will foam up high), mix well and pour right away into a buttered 9x13-inch baking pan. DO NOT SPREAD OUT, AIR WILL BE DEFLATED and candy will stick to teeth...When cool; break into pieces.
If you desire you can spread 1 cup of chocolate chips, white chips, butterscotch chips or mint chips on the hot candy in the pan and spread to coat the top and sprinkle with nuts before it cools.