The indicator plots a line with different colors using the Close price, the DRAW_COLOR_LINE drawing style is used.
Two indicator buffers are used: the first contains the closing price of the bar, the color indexes specified in the second indicator buffer. The colors of lines, the width and line style changed randomly after N=5 ticks.
The initial properties of the plot1 graphic plot are defined using the #property preprocessor directive, further these properties changed randomly (see OnCalculate() function).
See also The Drawing Styles in MQL5.