// =====================================================================
//  TURTLE  —  a tribute to Needlescript's Logo heritage
//
//  An imaginary needle drawing the very creature that guides it.
//  Carapace built from satin "scutes" (the plates on a real shell),
//  a tatami-filled body, four paddle-legs, head, and a seeded
//  speckle of stipple dots on the shell — change the seed, change
//  the markings, while the turtle herself stays put.
// =====================================================================

seed 7
let shell_w = 17       // [10:1:22] body half-width, mm
let shell_h = 22       // [14:1:28] body half-height, mm
let speckle_gap = 4    // [2:0.5:8] spacing between shell speckles, mm
stitchlen 2
fabric "woven          // free underlay + pull compensation, sews as previewed

//  helpers

// an oval as a closed region (path of points), centred at (cx, cy),
// half-width rx, half-height ry. steps points around the ellipse.
def oval(cx, cy, rx, ry, steps) [
  let p = []
  for i = 0 to steps - 1 [
    let a = i / steps * 360          // sweep a full turn, in degrees
    append(p, [cx + rx * sin(a), cy + ry * cos(a)])
  ]
  return p
]

// a single shell plate (scute): a small satin-outlined diamond,
// traced from the current spot, pointing outward along `heading`.
def scute(size) [
  satin 1.2
  push
  repeat 4 [
    fd size
    rt 90
  ]
  pop
  satin 0
]

//  1. the body  —  a broad tatami-filled oval underneath everything

color 1
fillangle 30
fillspacing 0.45
let body = oval(0, -2, shell_w, shell_h, 48)
up setpos(body[0]) down
beginfill
  sewpath(body)
endfill
trim

//  2. the four paddle-legs  —  satin ovals at the four diagonals

color 2

def leg(lx, ly, ang) [
  // a stubby paddle: trace a little satin oval tilted by `ang`
  satin 2.2
  let paddle = oval(0, 0, 4, 8, 24)
  // rotate + translate each point into place
  up
  let first = vadd(vrot(paddle[0], ang), [lx, ly])
  setpos(first)
  down
  for pt in paddle [
    setpos(vadd(vrot(pt, ang), [lx, ly]))
  ]
  setpos(first)        // close the loop
  satin 0
  trim
]

leg(-15,  12, -35)     // front-left
leg( 15,  12,  35)     // front-right
leg(-15, -16, -145)    // back-left
leg( 15, -16,  145)    // back-right

//  3. the head  —  a satin oval poking out the front, with two eyes

color 2
satin 2.6
let head = oval(0, 26, 6, 8, 24)
up setpos(head[0]) down
for pt in head [ setpos(pt) ]
setpos(head[0])        // close the loop
satin 0
trim

// eyes: two tiny bean-stitch dots
color 4
bean 3
up setxy(-2.6, 30) down  fd 0.4
trim
up setxy( 2.6, 30) down  fd 0.4
trim
bean 1

//  4. the carapace  —  a domed satin rim plus a field of scutes

color 3

// the shell rim: a satin oval just inside the body edge
satin 2.8
let rim = oval(0, -1, 14.5, 18.5, 40)
up setpos(rim[0]) down
for pt in rim [ setpos(pt) ]
setpos(rim[0])         // close the loop
satin 0
trim

// central column of scutes down the spine...
let spine = [16, 8, 0, -8, -16]
for sy in spine [
  up setxy(0, sy) down
  seth 0
  scute(2.6)
  trim
]

// ...flanked by two side columns
let sideY = [11, 2, -7]
for sy in sideY [
  up setxy(-7, sy) down
  scute(2.3)
  trim
  up setxy(7, sy) down
  scute(2.3)
  trim
]

//  5. seeded speckle  —  stipple dots scattered across the shell,
//     kept inside the rim region so the markings never stray off-shell

color 4
let dots = scatter(speckle_gap, rim) // Poisson-disc points, clipped to the shell
for d in dots [
  up setpos(d) down
  bean 3
  fd 0.3                        // a single bold tack = one speckle
  bean 1
  trim
]

// a Logo signature: the turtle has drawn herself.
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