gistfile1.txt

Red/System []

sphere!: alias struct! [
    radius [integer!]
]

list: declare struct![
    item1 [sphere!]    
    item2 [sphere!]
    item3 [sphere!]
]

list/item1: declare sphere!
list/item2: declare sphere!
list/item3: declare sphere!
list/item1/radius: 1
list/item2/radius: 2
list/item3/radius: 3

print [as integer! list/item1/radius " " list/item2/radius " " list/item3/radius lf]

item: declare sphere!
item: list/item1
i: 1
until [
    print [i " " item/radius lf]
    item: item + 1
    i: i + 1
    i > 3
]