% ex04.m4
.PS
   dot
   Point_(225)
{B1: ebox ; b_current; dlabel(dimen_*0.4,-0.1,i_1)
   dot
 B4: ebox(from rvec_(rp_len,0) to Here); b_current; dlabel(dimen_*0.4, 0.1,i_4)
   dot(at B4.start)}
   Point_(-45)
 B2: ebox ; b_current; dlabel(dimen_*0.4, 0.1,i_2)
   dot
 B7: ebox ; b_current; dlabel(dimen_*0.4, 0.1,i_7)
   dot
 B3: ebox(from B1.end to B2.end); b_current; dlabel(dimen_*0.4,0.1,i_3)
   dot(at (B1.start,B7.end))
{B5: ebox(to B1.end); b_current; dlabel(dimen_*0.4,-0.07,i_5)}
{B6: ebox(to B2.end); b_current; dlabel(dimen_*0.4, 0.07,i_6)}
{B8: ebox(right_ to B4.start); b_current; dlabel(dimen_*0.4, 0.1,i_8)}
 B9: ebox(left_ to B7.end); b_current; dlabel(dimen_*0.4,-0.1,i_9)
.PE