If you look at the d3.shape API (https://github.com/d3/d3-shape), you can see all the different standard shapes provided by D3, and you'll notice that we've already discussed most of them in the previous chapters. However, there is one part of this API that we haven't explored yet, and that is the symbols.
D3 provides a number of standard symbols that you can use in your visualizations. For instance, when drawing a line chart, instead of drawing circles for each point of the chart, you could use a cross or a star. D3 comes with the following list of standard symbols:
- d3.symbolCross: A cross symbol, or an addition (+) symbol
- d3.symbolCircle: A simple circle
- d3.symbolDiamond: A diamond symbol, as used on playing cards
- d3.symbolSquare: A simple square
- d3.symbolStar: A five pointed star
- d3.symbolTriangle: A simple triangle, point up
- d3.symbolWye: A Y symbol
Each of these symbols...
