Type 2 pattern of etched enamel is also known as:

According to Silverstone et al and Galil Wright  Type I Selective removal of enamel prism cores. Peripheries intact (honeycomb appearance). Type II   Reverse process.  Peripheries removed.  Cores intact (cobble stone appearance  with prism edges lost). Type III is the mixture of pattern I and II. Type IV – Pitted enamel with map like appearance. Type V – flat smooth surfaces