reset
fn = 'hexagons.dat'
S = 0.5
C = sqrt(3)/2
A = 1/C
a = 0.95*A

hex_id = 1

cmd = ''

hex_cmd(x, y, c) = sprintf("set obj hex_id poly from %g,%g-a to %g+a*C, %g-a*S to %g+a*C,%g+a*S to %g,%g+a to %g-a*C,%g+a*S to %g-a*C,%g-a*S to %g,%g-a fs solid 0.8 border lc pal cb %g lw 2 fc pal cb %g; hex_id = hex_id + 1;", x,y,x,y,x,y,x,y,x,y,x,y,x,y,c,c)

read_f(x, y, c) = (cmd=cmd.hex_cmd(x, y, c), y)

set term unknown

plot fn using 1:(read_f($1,$2,$3))

set term pop

print cmd
eval cmd

set size ratio -1
set xr [GPVAL_X_MIN-A:GPVAL_X_MAX+A]
set yr [GPVAL_Y_MIN-A:GPVAL_Y_MAX+A]

set term svg
#plot fn using 1:2:3 w d lc pal notit
plot fn using 1:2:3 notitle lc pal w d