d      f      e      b      c     a      
    ioc    utvg   ggtfk  otenqb wdt    wdt   sreg   
    hnjef  ioc    ibkj   hnjef  unhhh  ibkj  otenqb 
    ormf   ormf   mbwcun ibkj   hnjef  ormf  utvg   
  * unhhh  wdt    utvg   hnjef  ibkj   hnjef wzbp   
    mgv    ibkj   wzbp   ibkj   mbwcun wdt   hnjef  
  * ggtfk  otenqb wzbp   wzbp   ormf   ibkj  ibkj   
  * wdt    mgv    ormf   ggtfk  ormf   wzbp  mbwcun 
    sreg   mbwcun ibkj   ibkj   wdt    wzbp  mbwcun 
  * wzbp   mbwcun wdt    wdt    ggtfk  ibkj  sreg   
  * mbwcun ioc    ibkj   ioc    ormf   hnjef ibkj   
→   utvg   utvg   ggtfk  wzbp   hnjef  sreg  mgv    
  * otenqb wdt    sreg   mbwcun unhhh  sreg  otenqb 
  * ibkj   mbwcun wzbp   ioc    unhhh  hnjef wzbp