valley floor step

glacial step

Glacial Valley

glacial valley (galical-carved valley)

glacial valley lake

aggraded valley floor

valley floor

valley floor basement

valley floor divide

The super-wisdom valley The Bo Ruo Valley

valley in valley

Valley-in-Valley

floor quarryquarry tile floor tile

loaded floor by floor

AMFP forward step by step

approach step by step

course of breakdown step by step

decompression step by step

Differenlc-tension step by step