The letters of the original CGAL logo were made following:
David Lance Goines,
A Constructed Roman Alphabet: a Geometric Analysis
of the Greek and Roman Capitals and of the Arabic Numerals.
David R. Gordine, Boston, 1982.
Here are, for example, the precise instructions to construct the letter 'C':
- Construct first a square ABCD, and bisect AC at E, BD at F, AB at G, and CD at H.
- Draw the straight lines EF and GH, thereby establishing a point I at their intersection.
- From the center I, describe a circle JIK on EF, the diameter of which is one-ninth the distance AB.
- Using that same radius, describe a circle LJI, thereby establishing a point N on the perimeter of the circle I.
- Using that same radius, describe a circle IKM, thereby establishing a point O on the perimeter of the circle I.
- Draw the straight line NO, and produce it to intersect AG at P and HD at Q.
- From the point I, construct a line at right angles to PQ, thereby establishing on the perimeter of the circle I the points T and S.
- Produce IT to intersect EC at Y.
- From the center I, describe a circle Z tangential to AB, thereby establishing on PN a point R.
- Using the radius IK, describe from the center R a circle VRU.
- Using that same radius, decribe circles from the centers V and U.
- Bisect the intersections of the circles V and R, thereby establishing a point W on VR.
- Bisect the intersections of the circles R and U, thereby establishing a point X on RU.
- From the center I, describe a circle e intersecting the point W.
- From the center I, describe a circle f intersecting the point X.
- From the center S, describe a circle g intersecting the point R.
- Using the same radius, describe a circle h from the center T.
- From the center O describe a circle i tangential to the circles e and h.
- From the center H, describe an arc k tangential to the circle i, and intersecting BF.
- Describe an arc l from the center G tangential to the circle h and intersecting FD.
- From the center G, describe an arc m tangential to the circle f and intersecting FD.
- Describe from the center H an arc n tangential to the circle f and intersecting BF.
- Draw the straight line HF, thereby establishing a point d on IQ.
- From the center Y, describe an arc a intersecting the point Q and the line dF.
- Using the same radius, describe from the center A an arc b intersecting GB and the circle h.
- Using the radius IK, describe a circle c tangential to the interiors of the arcs n and b.
- From the center d, describe a circle tangential to the arc a and to the arc m.
Q.E.F.
