```source("http://macosa.dima.unige.it/r.R")    # If I have not already loaded the library
---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
# Example: average consumption of kg of fresh fruit per year by an Italian.
year = c(1880,1890,1900,1910,1920,1930,1940,1950,1960,1970,1980)
fruit = c(19,  21,  23,  28,  31,  27,  23,  37,  65,  88,  79)
# max is useful for choosing the "Plane": I find the maximum is 88, so I change y
# between 0 and 90
max(fruit)
# [1] 88
BF=4; HF=2.5
Plane(1880,1980, 0,90)
polyline(year,fruit, "blue"); POINT(year,fruit,"brown")

# I also put two inscriptions along the axes with these commands:
abovex("year"); abovey("fruit")

# Let's see how to enter the data in tabular form.
# I prepare an 11-row, 2-column table. I call it G.
G = array(dim=c(11,2))
# With:
data.entry(G)
# I insert data (and names) in the table on the left obtaining the table on the right:

# Then I click [X]. With:
G
# I obtain:
year fruit
[1,] 1880    19
[2,] 1890    21
[3,] 1900    23
[4,] 1910    28
[5,] 1920    31
[6,] 1930    27
[7,] 1940    23
[8,] 1950    37
[9,] 1960    65
[10,] 1970    88
[11,] 1980    79

# G[1,1] is 1880, G[1,2] is 19, G[2,1] is 1890, .., G[11,2] is 79.

BF=4; HF=2.5
Plane(1880,1980, 0,90)
polyline(G[1:11,1],G[1:11,2],"blue")
POINT(G[1:11,1],G[1:11,2],"brown")
abovex("year"); abovey("fruit")

more

```