Examples

scene plane {
  x: [-5, 5]
  y: [-5, 5]
  grid
  axes

  param t = 0 { range: [-3, 3] }
  bool show = false

  curve f = x^2 { color: primary }
  point p = (t, t^2) { drag: x -> t, color: accent }
  line tangent { through: p, slope: 2*t, style: dashed, show: show }

  label at (t, t^2+0.6) = "slope = ${2*t}" { show: show }

  slider t { label: "move the point" }
  toggle show { label: "show tangent line" }

  step "here's f(x) = x²"
  step "the tangent at any point x has slope 2x" { set: { show: true } }
  step "drag the point, watch the slope update" { animate: { t: 3 }, dur: 2000, ease: easeInOut }
}

scene plane {
  x: [-2.5, 2.5]
  y: [-2, 2]
  grid
  axes

  param t = 0 { range: [0, 360] }

  circle unit = (0,0) { r: 1, color: neutral, style: dashed }
  point p = (cos(t*PI/180), sin(t*PI/180)) { color: accent }

  line xproj = (0,0) -> (cos(t*PI/180), 0) { color: primary, style: dashed }
  line yproj = (cos(t*PI/180),0) -> (cos(t*PI/180), sin(t*PI/180)) { color: accent, style: dashed }

  vector rad = (0,0) -> (cos(t*PI/180), sin(t*PI/180)) { color: primary }

  label at (0.5, -0.2) = "cos = ${cos(t*PI/180)}"
  label at (1.4, 0.4) = "sin = ${sin(t*PI/180)}"

  slider t { label: "angle (degrees)", min: 0, max: 360 }
}

scene plane {
  x: [-0.5, 5]
  y: [-0.5, 10]
  axes

  curve f = x^2 { color: primary }

  for i in range(0, 10) {
    rect f"r{i}" = (i*0.5, 0) { w: 0.48, h: (i*0.5)^2, color: accent, opacity: 0.35 }
  }

  label at (2.5, 9) = "area ≈ sum of rectangles"
}

scene plane {
  x: [-5, 5]
  y: [-5, 5]
  grid
  axes

  param ax = 2 { range: [-4, 4] }
  param ay = 1 { range: [-4, 4] }
  param bx = 1 { range: [-4, 4] }
  param by = 3 { range: [-4, 4] }

  vector va = (0,0) -> (ax, ay) { color: primary }
  vector vb = (0,0) -> (bx, by) { color: accent }
  vector vsum = (0,0) -> (ax+bx, ay+by) { color: success }

  line pa = (ax,ay) -> (ax+bx,ay+by) { style: dashed, color: primary }
  line pb = (bx,by) -> (ax+bx,ay+by) { style: dashed, color: accent }

  point endA = (ax, ay) { drag: xy -> (ax,ay), r: 7, color: primary }
  point endB = (bx, by) { drag: xy -> (bx,by), r: 7, color: accent }

  label at (ax/2-0.3, ay/2) = "a"
  label at (bx/2+0.1, by/2) = "b"
  label at ((ax+bx)/2+0.2, (ay+by)/2+0.3) = "a + b"
}

scene plane {
  x: [-1, 9]
  y: [-7, 7]
  axes

  param cx = 3 { range: [1, 7] }
  param cy = 3 { range: [1, 6] }

  rect sq_a = (0,0-cx) { w: cx, h: cx, color: primary, opacity: 0.25 }
  rect sq_b = (cx,0) { w: cy, h: cy, color: accent, opacity: 0.25 }

  line side1 = (0,0) -> (cx,0) { color: neutral }
  line side2 = (cx,0) -> (cx,cy) { color: neutral }
  line side3 = (0,0) -> (cx,cy) { color: success }

  point v = (cx, cy) { drag: xy -> (cx,cy), color: accent, r: 7 }

  label at (cx/2, 0-cx/2) = "a² = ${cx*cx}"
  label at (cx+0.3, cy/2) = "b² = ${cy*cy}"
  label at (cx/2-1, cy/2+0.5) = "c² = ${cx*cx+cy*cy}"
}

scene plane {
  x: [-5, 6]
  y: [-5, 6]
  grid
  axes

  label at (-4.5, 5) = "predict: y = (x-1)² - 3"

  reveal {
    curve f = (x-1)^2 - 3 { color: primary, width: 3 }
    point vertex = (1, -3) { color: accent, r: 6, label: "vertex" }
  }
}

scene plane {
  x: [-7, 7]
  y: [-4, 4]
  grid
  axes

  param A = 1 { range: [0.1, 3] }
  param f = 1 { range: [0.1, 4] }
  param phi = 0 { range: [-3, 3] }

  curve wave = A * sin(f*x + phi) { color: primary }
  curve ref = sin(x) { color: neutral, style: dashed }

  label at (0.3, A+0.3) = "y = ${A}·sin(${f}x + ${phi})"

  slider A { label: "amplitude A", min: 0.1, max: 3 }
  slider f { label: "frequency f", min: 0.1, max: 4 }
  slider phi { label: "phase shift φ", min: -3, max: 3 }
}