Canvas.setpenopacity(1);

const turtle = new Turtle();

// ----------------------
// PARAMETERS
// ----------------------
const scale = 1             // scaling factor
const spacing = 2*scale;    // distance between columns
const L = 200;           // rectangle length (horizontal)
const W = 100;            // rectangle width (vertical)

const n = 4;             // number of segments in full column
const l = 21;             // length of each vertical segment

const left_clamp = 25*scale 
const right_clamp = 25*scale 

// ----------------------
// DERIVED VALUES
// ----------------------
const d = (W - n*l)/(n-1); // Overlapping length
const e = (d + l) / 2       // Offset of the second raw of cuts

// bottom-left corner of centered rectangle
const x0 = -L / 2;
const y0 = -W / 2;

// ----------------------
// DRAW RECTANGLE
// ----------------------
turtle.penup();
turtle.goto(x0, y0);
turtle.setheading(0);
turtle.pendown();

turtle.forward(L);
turtle.right(90);
turtle.forward(W);
turtle.right(90);
turtle.forward(L);
turtle.right(90);
turtle.forward(W);
turtle.right(90);

// ----------------------
// DRAW COLUMN FUNCTION
// ----------------------
function drawColumn(x, yStart, count) {
  turtle.penup();
  turtle.goto(x, yStart);
  turtle.setheading(90); // vertical up

  for (let i = 0; i < count; i++) {
    turtle.pendown();
    turtle.forward(l);

    turtle.penup();
    turtle.forward(d);
  }
}

// ----------------------
// DRAW PATTERN
// ----------------------
let x = x0 + left_clamp;

while (x <= x0 + L - right_clamp) {

  // full column (n segments) starting at y =  -W/2
  drawColumn(x, -W/2, n);

  // offset column (n-1 segments) at x + spacing, starting at y = e  -W/2
  const x2 = x + spacing;
  if (x2 <= x0 + L - right_clamp) {
    drawColumn(x2, e -W/2, n - 1);
  }

  // move to next pair
  x += spacing * 2;
}