nomainwin

open "test" for graphics_nsb_fs as #gr

#gr "trapclose quit"
#gr "down; home"
#gr "posxy cx cy"

order =10

w =cx *2: h =cy *2

dim a( h, h)  'line, col

#gr "trapclose quit"
#gr "down; home"

a( 1, 1) =1

for i = 2 to 2^order -1
    scan
    a( i, 1) =1
    a( i, i) =1
    for j = 2 to i -1
        'a(i,j)=a(i-1,j-1)+a(i-1,j)         'LB is quite capable for crunching BIG numbers
        a( i, j) =(a( i -1, j -1) +a( i -1, j)) mod 2  'but for this task, last bit is enough (and it much faster)
    next
    for j = 1 to i
        if a( i, j) mod 2 then #gr "set "; cx +j -i /2; " "; i
    next
next
#gr "flush"

wait

sub quit handle$
    close #handle$
    end
end sub