This math image could be re-created using vector graphics as an SVG file. This has several advantages; see Commons:Media for cleanup for more information. If an SVG form of this image is available, please upload it and afterwards replace this template with {{vector version available|new image name}}. It is recommended to name the SVG file “Neusis-heptagon.svg”—then the template Vector version available (or Vva) does not need the new image name parameter.

Geometric details: OPQR is a unit square. The arc centred on O through Q is drawn, as is the perpendicular bisector of OP. The en:Neusis construction involves finding unit interval AB through P with A on the perpendicular bisector and B on the arc. Angle PAO is the interior angle of a heptagon. The remainder of the construction can be carried out with ruler and compass. (Two of the vertices lie on the lines OR and PQ.)

The en:MetaPost source below is a bit of a cheat.

Ja, vlasnik autorskog prava ovog djela, ovdje ga objavljujem pod sljedećim licencama:

Dopušteno je umnožavanje, dijeljenje i mijenjanje ovog dokumenta pod uslovima GNU-ove licence za slobodnu dokumentaciju, verzije 1.2 ili bilo koje novije koju objavi Fondacija za slobodni softver; bez nepromjenljivih odjeljaka i bez tekstova na naslovnoj i zadnjoj strani. Tekst licence možete pročitati ovdje.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue

	Ova datoteka dostupna je pod licencom Creative Commons Attribution-Share Alike 3.0 Unported.
	Slobodno smijete: dijeliti – umnožavati, raspodjeljivati i prenositi djelo prerađivati – prilagođavati djelo Pod sljedećim uslovima: pripisivanje – Morate pripisati odgovarajuće autorske zasluge, osigurati vezu do licence i naznačiti jesu li napravljene izmjene. To možete uraditi na bilo koji razumni način, ali ne tako da se sugerira da davalac licence odobrava Vas ili Vašu upotrebu njegovog djela. dijeljenje pod istim uslovima – Ako mijenjate, preoblikujete ili nadograđujete ovaj materijal, morate ga objaviti pod istom ili sličnom licencom.
	Ova oznaka licence je dodana na ovu datoteku kao dio GFDL ažuriranja licence.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue

Ova datoteka je licencirana pod Creative Commons Attribution-Share Alike 2.5 generičkom, 2.0 generičkom i 1.0 generičkom licencom.

Slobodno smijete:

• dijeliti – umnožavati, raspodjeljivati i prenositi djelo
• prerađivati – prilagođavati djelo

Pod sljedećim uslovima:

• pripisivanje – Morate pripisati odgovarajuće autorske zasluge, osigurati vezu do licence i naznačiti jesu li napravljene izmjene. To možete uraditi na bilo koji razumni način, ali ne tako da se sugerira da davalac licence odobrava Vas ili Vašu upotrebu njegovog djela.
• dijeljenje pod istim uslovima – Ako mijenjate, preoblikujete ili nadograđujete ovaj materijal, morate ga objaviti pod istom ili sličnom licencom.

https://creativecommons.org/licenses/by-sa/2.5CC BY-SA 2.5 Creative Commons Attribution-Share Alike 2.5 truetrue

Izaberite licencu po vašem izboru.

The Metapost source for this file. All done via command line on MacOSX:

• Metapost (mpost command from teTeX)
• \convertMPtoPDF TeX command from supp-pdf.tex, processed via pdfTeX
• ghostscript to a png at 1200x1200.

I hereby make this source available under the GPL version 2 or later.

u=2cm;
path unitcircle;   unitcircle=fullcircle scaled 2u;
thick=1mm;
thin=0.25mm;
transform heptT;
def drawruler(expr p,q) =
    path ruler[];
    ruler0:=unitsquare xscaled abs(p-q) yscaled .1u rotated angle(q-p) shifted p;
    ruler1:=unitsquare yscaled 0.5 shifted 0.25up
        xscaled abs(p-q) yscaled .1u rotated angle(q-p) shifted p;
    fill ruler0 withcolor (1,1,.5);
    fill ruler1 withcolor (.9,.9,.3);
    draw ruler0 withpen pencircle scaled 0.25;
    enddef;
beginfig(77)
    pickup  pencircle scaled thin;
    z0=(0,0);      z0d=(0,.4u);
    z1=(-0.5u,0);  z1l=(.5u-u*sqrt(2),0);
    z2=(0.5u,0);
    z3=(.5u,-u);   z3u=(.5u,-u*sqrt(2));
    z4=(-.5u,-u);
    z5=(0,-u);
    z6=(0,whatever)=z1+whatever*dir(180/7);
    z7=z6-u*dir(180/7);
    drawruler(z6,z7);
    drawruler(z3,z4);
    for i = 0 upto 7:
        z[i]vtx=dir(360i/7);
    endfor;
    xxpart heptT= yypart heptT;
    xypart heptT=-yxpart heptT;
    for i = 6,7: z[i] = z[i]vtx transformed heptT; endfor
    draw (for i = 0 upto 6: z[i]vtx -- endfor cycle) transformed heptT dashed evenly withcolor blue;
    draw z1--z2--z3--z4--cycle;
    draw z1l--z1;
    draw z0d--z5;
    draw z2--z4 dashed evenly;
    draw z6--z7;
    label.urt("O",z2);
    label.ulft("A",z6);
    label.ulft("P",z1);
    label.llft("Q",z4);
    label.rt("R",z3);
    label.lft("B",z7);
    draw subpath (4,5) of unitcircle scaled (sqrt(2)) shifted z2;
    for i = 1,2,6,7,3,4:
        if known(x[i]):
            drawdot z[i] withpen pencircle scaled thick;
        fi
    endfor
endfig;    
bye

• Image:Neusis-trisection.png