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