Generate sf objects (7)

# exterior ring
p1 <- rbind(c(10, 0), c(11, 0), c(13, 2),
            c(12, 4), c(11, 4), c(10, 0))
p1

##      [,1] [,2]
## [1,]   10    0
## [2,]   11    0
## [3,]   13    2
## [4,]   12    4
## [5,]   11    4
## [6,]   10    0

# hole
p2 <- rbind(c(11, 1), c(11, 2), c(12, 2), c(11, 1))
p2

##      [,1] [,2]
## [1,]   11    1
## [2,]   11    2
## [3,]   12    2
## [4,]   11    1

# polygon including hole
pol_sfg <- st_polygon(list(p1, p2))
pol_sfg

## POLYGON ((10 0, 11 0, 13 2, 12 4, 11 4, 10 0), (11 1, 11 2, 12 2, 11 1))