source: CGBLisp/examples/pappus4.macsyma@ 1

if get('geometry2,'version)=false then load(geometry2);
/* Pappus theorem;
9 points and 9 lines
Points: a0, a1, a2, b0, b1, b2, c0, c1, c2
line            contains points
l0              a0 b1 c0
l1              a0 b2 c1
l2              a1 b0 c0
l3              a1 b2 c2
l4              a2 b0 c1
l5              a2 b1 c2
l6              a0 a1 a2
l7              b0 b1 b2
l8              c0 c1 c2
*/
/* Specs */
a00:a10:0; a20:1;
a01:1; a11:0; a21:1;
a12:0; a22:1; /* a02 # 0 */
l06:0; l16:1; l26:0;

for i:0 thru 2 do (
        a[i]:[concat('a0,i),concat('a1,i),concat('a2,i)],
        b[i]:[concat('b0,i),concat('b1,i),concat('b2,i)],               
        c[i]:[concat('c0,i),concat('c1,i),concat('c2,i)]
);              

for i:0 thru 8 do 
        l[i]:[concat('l0,i),concat('l1,i),concat('l2,i)];

rel(l,a,b,c):=[l.a,l.b,l.c];

eqns:append(
[1-v*collinear(c[0], c[1], c[2])],
rel(l[0],a[0], b[1], c[0]),
rel(l[1],a[0], b[2], c[1]),
rel(l[2],a[1], b[0], c[0]),
rel(l[3],a[1], b[2], c[2]),
rel(l[4],a[2], b[0], c[1]),
rel(l[5],a[2], b[1], c[2]),
rel(l[6],a[0], a[1], a[2]),
rel(l[7],b[0], b[1], b[2]));


vars:append(makelist(l[j],j,0,7),
        makelist([c[i]],i,0,2),[a[2],b[2]]);
params:makelist([a[i],b[i]],i,0,1);
vars:''vars;
params:''params;
vars:listofvars(vars);
params:listofvars(params);
cover:expand([[[],[]]]);
eqns:expand(''eqns);
cover:expand(''cover);
stringout("pappus4.out",eqns,vars,params,cover);