size(8cm,0);

path profil=cross(3,round=false,r=0.3),
     p=(0,0)---(1,1)..(2,0);
pen stylo=makepen(scale(10)*profil)+grey;

draw(p,stylo);
dot(p,stylo+red);

dot(point(p,1.57),stylo+orange);
dot(point(p,1.6),stylo+green);
dot(point(p,1.63),stylo+blue);

draw(p,linetype("4 4"));