1 \documentclass[12pt]{standalone}
4 \usepackage[utf8x]{inputenc}
6 \usepackage[T1]{fontenc}
8 \renewcommand{\rmdefault}{ugm}
9 \renewcommand{\sfdefault}{phv}
10 \usepackage[garamond]{mathdesign}
12 \usetikzlibrary{positioning, shapes, arrows, shadows}
16 observed/.style={circle, draw},
17 partly observed/.style 2 args={draw, fill=#2, path picture={
18 \fill[#1, sharp corners] (path picture bounding box.south west) -|
19 (path picture bounding box.north east) -- cycle;},
21 unobserved/.style={draw, circle, fill=gray!40},
22 residual/.style={draw, rectangle}
28 \node[unobserved] (y) {$Y$};
30 \node[observed={white}{gray!40}, above=of y] (x) {$X$};
31 \node[observed, left=of x] (w) {$W$};
33 % \node[unobserved, above=of w] (k) {$K$};
34 \node[observed,right=of x] (z) {$Z$};
35 % \node[residual,below=of y] (e) {$\varepsilon$};
36 % \node[residual,below=of w] (xi) {$\xi$};
38 % \draw[->] (x) -- (w);
40 % \draw[->] (k) -- (w);
42 % \draw[->] (z) -- (k);
43 % \draw[->] (y) -- (xi);
44 % \draw[->] (w) -- (xi);