PAUSED

Controls

Left mouse	Place element with brush
C	Clear
Shift + C	Clear without border
P	Toggle pause
1-4	Select primary brush element
Shift + 1-4	Select secondary brush element (used for placing structures)
N	Step simulation while paused
S	Place sieve
Shift + S	Place wide sieve
D	Place diagonals in a V shape
Shift + D	Place shallow diagonals in a V shape
F	Place floor
G	Place grid
Shift + G	Place alternating grid
B	Place box
Shift + B	Place filled box using secondary brush for the border and primary brush for the fill
R	Place square using primary brush