My first time in Rebol and numbers

Rebol is a fantastic language!
You can try this code in the Rebol/view Console:
numbers.r

REBOL [Title: "Numbers Test"]
ena: 121
positions: []
dimPal: 3

unitar: func [ ele enne ][ either (( (ele // enne) == 1 ) or (( ele // enne) == (enne - 1)))[ 1  ] ["-"] ]

evaluateUni: func [ en ] [
for j 1 en 1[ st: copy ""
for i 1 en 1[
append st unitar i * j en
sr: square-root en
if ( unitar i * j en ) == 1  [ append positions ( as-pair i j  ) * 350 / en + 23x23 ]
]
]
positions
]
evaluateUni ena

refre: does[
positions: copy []
evaluateUni ena
pis: copy []
posi: copy positions
foreach p posi[ insert tail pis  reduce[ 'fill-pen 160.209.215.100 'circle p dimPal ]  ]
out: form ( length? positions ) / 2 == ( ena - 1 )
insert tail pis reduce [  'text 230x5 join "numero primo: "   out ]
scrn/effect/draw: copy []
append scrn/effect/draw pis
show scrn
]

refreNoEval: does[
pis: copy []
posi: copy positions
foreach p posi[ insert tail pis  reduce[ 'fill-pen 160.209.215.100 'circle p dimPal ]  ]
out: form ( length? positions ) / 2 == ( ena - 1 )
insert tail pis reduce [  'text 230x5 join "numero primo: "   out ]
scrn/effect/draw: copy []
append scrn/effect/draw pis
show scrn
]
lay: layout [

scrn: box 400x400 black effect [
draw [ text "unit" ]
rotate 50
gradmul 180.180.210 180.60.255
]
slider 200x16 ena / 300 [
ena: to-integer value * 300
inpNum/data: form ena
inpNum/text: form ena
show inpNum
refre
]
inpNum: field form ena [
print to-integer inpNum/text
ena: to-integer inpNum/text 
]
at 330x460
btn "Change"  [
refre
]
slider 100x15 dimPal / 10 [
dimPal: to-integer  value    * 10
refreNoEval
]
]

view lay