library pgraph;
graphset;

/* figure with dips in both series */

if 0;
px = seqa(1,1,130);
adder = zeros(50,1)|sin(seqa(1,1,30)/(30)*pi)|zeros(50,1);
c = (px-30*adder);                        /* c line */
y = (80+px-3*30*adder);                 /* y line */
py = c~y~(c-y);
ytics(-130,220,220+130,0);
xtics(0,130,130,0);
_Pnum = 0;
_Pltype = 6|3|6;
_Pmsgstr = "c\000y\000c-y";
fill = 1|1|1;
_Pmsgctl =  ( 100*fill )~(py[100,.]'+(10|10|10))~(fill*(.2~0~0~10));
xlabel("Time");
_Ptek = "figa.tkf";
xy(px,py);
endif;

if 1;
px = seqa(1,1,130);
c = .5*px + 100*sin(pi*30/40)*(zeros(50,1)|ones(80,1));
adder = zeros(10,1)|
        sin(seqa(0,1,20)/20*pi)|
        zeros(20,1)|
        sin(seqa(0,1,30)/40*pi)|
        sin(pi*30/40)*ones(50,1);
y = 90 + .5*px + 100*adder;
py = c~y~(c-y);
_Pnum = 0;
_Pltype = 6|3|6;
_Pmsgstr = "c\000y\000c-y";
fill = 1|1|1;
_Pmsgctl =  ( 100*fill )~(py[100,.]'+(10|10|10))~(fill*(.2~0~0~10));
xlabel("Time");
xtics(1,130,130,0);
ytics(-200,270,270+200,0);
_Ptek = "figb.tkf";
xy(px,py);
endif;