Consider a single sigmoid threshold unit with three inputs, x$1,$ x$2,$ and x$3.$

y $=$g$($w$0+$w$1$x$1+$w$2$x$2+$w$3$x$3)$ where g$($z$)=1/1+$exp$($z$)$

We input values of either $0$ or $1$ for each of these inputs. Assign values to weights

w$0,$ w$1,$ w$2$ and w$3$ so that the output of the sigmoid unit is greater than $0\mathrm{.}5$ if an

only if $($x$1$ AND x$2)$ OR x$3.$