conec=[1 2 3;3 2 4;4 2 5];
coord=[4 8 4 8 12;
       2 2 6 8 4 ];
nel=size(conec,1);npe=size(conec,2);
nod=size(coord,2);

xhat=[1/8:1/8:6/8 1/8:1/8:5/8 1/8:1/8:4/8 1/8:1/8:3/8 1/8 2/8 1/8;
1/8*ones(1,6) 2/8*ones(1,5) 3/8*ones(1,4) 4/8*ones(1,3) 5/8 5/8 6/8];
nhat=size(xhat,2);
[g dg d2g] = masterp1(2,xhat);

figure 1;

for k=1:nel
XX(:,1)=coord(:,conec(k,1));
XX(:,2)=coord(:,conec(k,2));
XX(:,3)=coord(:,conec(k,3));
x=zeros(2,nhat);
for i=1:npe
x(1,:)=x(1,:)+XX(1,i)*g(i,:);
x(2,:)=x(2,:)+XX(2,i)*g(i,:);
end
d=k; scatter(x(1,:),x(2,:),20,d,"filled")
hold on;
d=8; scatter(XX(1,:),XX(2,:),20,d,"filled")
end
hold off