abstract
bars
bed
behind
building
cage
cell
concept
convict
crime
criminal
custody
despair
dig
escape
gone
grey
grunge
guards
hole
inside
iron
jail
jailbird
locked
looking
macro
metal
metallic
nail
object
pattern
penitentiary
prison
punishment
sand
shapes
shiny
silver
steel
strong
symbol
three
tool
tunnel
wall