I've created a coloured frame which sits around the Plicker - A = Green, B = Red, C = Amber (and for completeness D = Blue). This way the Plicker cards double as a traffic light formative assessment card (this strategy involves a quick visual snapshot of students' level of understanding of a concept (i.e. students hold up green for 'all ok', amber for 'sort of' and so on). On the frame A also has a 'Yes', B a 'No' and C a 'Depends'. This is really handy when you want a quick response without recording responses. It does remove the anonymity aspect, however.