2
2
.
.
4
4
P
P
l
l
a
a
y
y
g
g
r
r
o
o
u
u
n
n
d
d
s
s
I
I
n
n
f
f
o
o
[
[
R
R
]
]
XCode Play
grounds
allows yo
u to quickly
test
so
me Sw
ift co
de.
