mutliples readkeys at the same time, serial recall response

Hello all,

I'm having difficulty coding my response screen for an immediate serial recall task.
After having seen 6 words I would like for participant to be able to type the six words on the screen and have their answers kept on the screen as they go. 
I'm trying to use the placeholders and the readkeys function to present six empty boxes that should end up being all being filled. 
But I can figure out how to integrate draw off/on and readkeys together correctly. 

Here's what I have now :

task recall
font big
table words
show text "+"
delay 500
clear -1
show text @1
delay 1000
clear -1
show text @2
delay 1000
clear -1
show text @3
delay 1000
clear -1
show text @4
delay 1000
clear -1
show text @5
delay 1000
clear -1
show text @6
delay 1000
clear -1
font small
draw off
show text "Utilisez le clavier (avec majuscules vérouillées) pour tapper les" 0 -200
show text "mots dont vous vous souvenez, dans l'ordre présenté." 0 -150
show text "Appuyez sur « retour/enter » après chaque mot." 0 -100
show text "Appuyez sur « retour/enter » pour sauter un mot." 0 -50
draw on
font medium
readkeys option size 5
readkeys option space 20
draw off
readkeys option show -150 50
readkeys option placeholders 30 30
readkeys option show -150 100
readkeys option placeholders 30 30
readkeys option show -150 150
readkeys option placeholders 30 30
readkeys option show 150 50
readkeys option placeholders 30 30
readkeys option show 150 100
readkeys option placeholders 30 30
readkeys option show 150 150
readkeys option placeholders 30 30
readkeys @1 30000
readkeys @2 30000
readkeys @3 30000
readkeys @4 30000
readkeys @5 30000
readkeys @6 30000
draw on
delay 1000
clear -1
set $status STATUS
save @1 @2 @3 @4 @5 @6 $status WORD