Symmetrical 2 : Of the same size and shape, repetition of data or a series of data where one series of events is the same as the immediately preceding series over same period of time. (WT)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}