\coordinate (temp1) at ($(a-incoming boundary.west)!0.3!(a-outgoing boundary.west) +(0,0.08)$); \coordinate (temp2) at ($(a-incoming boundary.west)!0.7!(a-outgoing ...
every incoming lower boundary component/.style={draw}, every outgoing lower boundary component/.style={draw}, \coordinate (temp1) at ($(a-incoming boundary.west)!0.3 ...