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
Honeycomb pattern
Soap bubble pattern
Cobble stone pattern
Pyramid pattern