First I define two step functions:

```
julia> f(x)=floor(5x)-floor(2x)-floor(3x)
f (generic function with 1 method)
julia> g(x)=f(2x)-f(x)
g (generic function with 1 method)
```

and then I plot `g`

:

```
julia> using Plots
julia> gr()
Plots.GRBackend()
julia> plot(g,0,1,ylim=(-1.2,1.2))
```

So far, so good. Because `g`

is periodic with period 1, I try:

```
julia> plot(g,0,2,ylim=(-1.2,1.2))
```

The plotted graph is that of *the zero function for x between 0 and 1*, and is correct for x between 1 and 2 !!! To get the right graph, I must use something like

```
julia> plot(g,0:0.001:2,ylim=(-1.2,1.2))
```

Puzzling!