Plot of a periodic triangular wave

I'm trying to graph the zig-zag function at the top of this page: http://www.math.ubc.ca/~feldman/m321/nondiffble.pdf

I have a little bit of experience with Mathematica but not a ton. Any suggestions?

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Plot[Abs@TriangleWave[x/4], {x, -4, 4}, AspectRatio -> 1/8] – Dr. belisarius Apr 21 '14 at 18:16
You are amazing thank you. – Jacob Saltsky Apr 21 '14 at 18:41
Almost exactly the way it's defined in the PDF: f[x_] := Piecewise[{{Abs[x], -1 <= x <= 1}, {f[x + 2], x < 0}, {f[x - 2], x > 0}}] – Rahul Apr 21 '14 at 18:43

This is using the definition of $\phi(x)$ in the paper. Granted a bit more cumbersome than the triangle wave.

Plot[Piecewise[{
{Abs[x + 4], -5 < x < -3},
{Abs[x + 2], -3 < x < -1},
{Abs[x], -1 < x < 1},
{Abs[x - 2], 1 < x < 3},
{Abs[x - 4], 3 < x < 5}}],
{x, -4.15, 4.15}, PlotRange -> {0, 1}, AxesLabel -> {"x", "\[CurlyPhi](x)"},
LabelStyle -> Directive[Black, Bold, Medium],
Ticks -> {{-4, -3, -2, -1, 0, 1, 2, 3, 4}, {0, 1}},
AspectRatio -> 2/17, PlotStyle -> {Black, Thickness[.0025]},
ImageSize -> 500]


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