JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="canvas" height="400" width="400"></canvas>

JavaScript

var canvas = document.getElementById('canvas');
var cx = canvas.getContext('2d');
cx.lineCap = 'round';
cx.lineJoin = 'round';
cx.lineWidth = 40;

// Create the first line, 10% transparency, the whole length of the shape.
cx.strokeStyle = 'rgba(0,0,255,0.1)';
cx.beginPath();
cx.moveTo(20,20);
cx.lineTo(260,20);
cx.lineTo(220,60);
cx.stroke();
cx.closePath();

// Create the first part of the second line, first by clearing the first
// line, then 40% transparency.
cx.strokeStyle = 'black';
cx.globalCompositeOperation = 'destination-out';
cx.beginPath();
cx.moveTo(20,20);
cx.lineTo(100,20);
cx.stroke();
cx.strokeStyle = 'rgba(0,0,255,0.4)';
cx.globalCompositeOperation = 'source-over';
cx.stroke();
cx.closePath();

// Create the second part of the second line, same as above.
cx.strokeStyle = 'black';
cx.globalCompositeOperation = 'destination-out';
cx.beginPath();
cx.moveTo(180,20);
cx.lineTo(260,20);
cx.stroke();
cx.strokeStyle = 'rgba(0,0,255,0.4)';
cx.globalCompositeOperation = 'source-over';
cx.stroke();
cx.closePath();