:

## strange plot behavior

A colleague recently showed me some strange behavior when trying to plot vertical lines. The following works to create the unit square:

```plot( [x=0,x=1,0,1], x=0..1, y=0..1, color=black, axes=none ); # OK

```

But doubling the size in each direction does not produce a square:

```plot( [x=0,x=2,0,2], x=0..2, y=0..2, color=black, axes=none ); # BAD

```

The vertical lines extend only up to y=1, not y=2 as requested. The next command shows that vertical lines at the boundary are treated differently.

```plot( [x=0,x=1,0,2], x=0..2, y=0..2, color=black, axes=none ); # BAD
```
` `

I doubt I would have ever tried any of these commands. To put a border on a plot I would use axes=boxed or implicitplot:

plot(0, x=0..10, y=0..10, axes=boxed );
implicitplot( [x=0,x=10,y=0,y=10], x=0..10, y=0..10, color=blue, axes=none );

For more strangeness, explain why each of these plots includes y=0

```plots[display]( <
plot( [x=0,x=1,1], x=0..1, y=0..1, color=blue, axes=none ) |
plot( [x=0,x=2,1], x=0..2, y=0..2, color=blue, axes=none ) |
plot( [x=0,x=1,1], x=0..2, y=0..2, color=blue, axes=none ) > );
plots[display]( <
plot( [x=0,x=1], x=0..1, y=0..1, color=blue, axes=none ) |
plot( [x=0,x=2], x=0..2, y=0..2, color=blue, axes=none ) |
plot( [x=0,x=1], x=0..2, y=0..2, color=blue, axes=none ) > );

```

I tried to upload these plots to MaplePrimes, but Maple does not appear to export an array of plots (all I get is the last one in the array). Also, even though I select different local files, MaplePrimes insists on using only the first filename that I uploaded. Sorry. You will have to create the plots on your own.

Doug

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