beginfig(1);

numeric u,v;
u=6mm;
v=3mm;

drawarrow (-0.5u,0)--(10u,0);
drawarrow (0,-0.5v)--(0,10v);

draw (-0.1u,-0.4v)---(1u,4v)..(2u,5v)---
   (3u,5v)..(4u,7v)..(5u,9v)---(7u,9v)..(9.5u,1v)---(10u,1v);

label.bot(btex $t$ etex, (10u,0));
label.lft(btex $x$ etex, (0,10v));


endfig;
bye