 4; j++) { ctx.lineTo(patch.points[i][j].x, patch.points[i][j].y); }
                    ctx.stroke();
                }
                for (let j = 0; j < 4; j++) { 
                    ctx.beginPath(); ctx.moveTo(patch.points[0][j].x, patch.points[0][j].y);
                    for (let i = 1; i < 4; i++) { ctx.lineTo(patch.points[i][j].x, patch.points[i][j].y); }
                    ctx.stroke();
                }
            }

            _drawBezierSurface(ctx, patch, color, segments) {
              