All of the following German adjectives use implied comparisons as an alternative for the use of "very." What comparisons are used literally?

Matching exercise

  
Match the items on the right to the items on the left.
schnurgerade
kugelrund
butterweich
lupenrein
sonnenklar
bärenstark
mäuschenstill
messerscharf
steinhart
bildhübsch
spindeldürr
rabenschwarz
federleicht
hundsgemein
potthässlich
riesengroß
himmelhoch
felsenfest
bleischwer
blitzschnell
strohdumm
eiskalt
schneeweiß
kreidebleich