Rechteckfläche — Georg Nees, 1969

Dissertation 1969 · p. 142

ALGOL 60

1 'BEGIN'
2 'COMMENT' DEMONSTRATION RECHTECKFLÄCHE.,
3 'REAL' P, P1.,
4 OPEN(0,0), JI1.=JS1., JI2.=JS2.,
5 JA1.=0., JE1.=6., JA2.=-80., JE2.=80.,
6 P.=-130.,
7 ANFANG..
8 'IF' P 'GREATER' 130.0 'THEN' 'GOTO' FIN.,
9 P1.=P+J1., REC(P,P1,0.0,J2,0.4), P.=P1.,
10 'GOTO' ANFANG.,
11 FIN.. CLOSE
12 'END' DEMONSTRATION RECHTECKFLÄCHE.,

This page · drawing kernel

JavaScript

let P = -130;
while (P <= 130) {
  const P1 = P + J1(0, 6);
  REC(P, P1, 0, J2(-80, 80), 0.4);
  P = P1;
}
// REC fills with parallel strokes,
// spacing A = S − 0.1. Landscape
// horizontally, portrait vertically.
// Boolean B flips direction like
// a shuttle on a loom.

Section 2.3.2 introduces REC(D,E,F,G,S): a filled rectangle of closely spaced strokes, pen width S. A tenth of a unit of overlap (A = S−.1) closes the gaps. Landscape or portrait decides the fill direction — the longer side, so the plotter changes heading less often. Fig. 14: from P = −130 to the right, width J1 in 0…6, height J2 in ±80, almost all landscape. The sheet stands upright like the scan (90° clockwise).