input global; a := u/2; beginfig(1) path square; square = o--(a,0)--(a,a)--(0,a)--cycle; draw square; draw square scaled 3 shifted (-3a,0); draw square scaled 4 shifted (-3a,-4a); draw square scaled 5 shifted (a,-4a); draw square scaled 6 shifted (0,a); draw square scaled 6 shifted (0,7a); draw square scaled 7 shifted (-10a,-4a); draw square scaled 10 shifted (-10a,3a); endfig; a := u/5; path square; square = o--(a,0)--(a,a)--(0,a)--cycle; picture squares; squares = image( draw square scaled 17; draw square scaled 13 shifted (0,17a); draw square scaled 4 shifted (13a,17a); draw square scaled 9 shifted (13a,21a); draw square scaled 9 shifted (22a,21a); draw square scaled 7 shifted (17a,14a); draw square scaled 7 shifted (24a,14a); draw square scaled 14 shifted (17a,0); ); beginfig(2) draw squares; endfig; beginfig(3) draw squares; draw (0,17a)--(17a,17a) withpen thickline withcolor mycolour; label(btex $4$ etex,(13a,17a) + (4a,4a)/2); label(btex $x$ etex,(17a,17a)/2); label(btex $x-4$ etex,(0,17a) + (13a,13a)/2); endfig; beginfig(4) draw squares; label(btex $4$ etex,(13a,17a) + (4a,4a)/2); label(btex $x$ etex,(17a,17a)/2); label(btex $x-4$ etex,(0,17a) + (13a,13a)/2); draw (13a,17a)--(13a,30a) withpen thickline withcolor mycolour; label(btex $x-8$ etex,(13a,21a) + (9a,9a)/2); label(btex $x-8$ etex,(22a,21a) + (9a,9a)/2); endfig; beginfig(5) draw squares; label(btex $4$ etex,(13a,17a) + (4a,4a)/2); label(btex $x$ etex,(17a,17a)/2); label(btex $x-4$ etex,(0,17a) + (13a,13a)/2); label(btex $x-8$ etex,(13a,21a) + (9a,9a)/2); label(btex $x-8$ etex,(22a,21a) + (9a,9a)/2); draw (13a,21a)--(31a,21a) withpen thickline withcolor mycolour; label(btex $x-10$ etex,(17a,14a) + (7a,7a)/2); label(btex $x-10$ etex,(24a,14a) + (7a,7a)/2); label(btex $2x-20$ etex,(17a,0) + (14a,14a)/2); endfig; beginfig(6) draw squares; label(btex $4$ etex,(13a,17a) + (4a,4a)/2); label(btex $x$ etex,(17a,17a)/2); label(btex $x-4$ etex,(0,17a) + (13a,13a)/2); label(btex $x-8$ etex,(13a,21a) + (9a,9a)/2); label(btex $x-8$ etex,(22a,21a) + (9a,9a)/2); label(btex $x-10$ etex,(17a,14a) + (7a,7a)/2); label(btex $x-10$ etex,(24a,14a) + (7a,7a)/2); label(btex $2x-20$ etex,(17a,0) + (14a,14a)/2); draw (17a,0)--(17a,21a) withpen thickline withcolor mycolour; draw (0,0)--(0,30a) withpen thickline withcolor mycolour; draw (31a,0)--(31a,30a) withpen thickline withcolor mycolour; endfig; end