This activity is to get the students to be creative in creating and designing their own antigens and their complementary antibody pair.
Students are often asked to look at diagrams of blood types where the Type "A" antigens are usually in the shape of a triangle while the type "B" antigens are in a semi-circle form, but why not get the students be creative and come up with their own antigen / antibody pair.
I stress a lot on creativity in my classroom. To start this activity, prior knowledge of basic blood types should have been done. I typically draw sample red blood cells with proper antigens on the surface to denote blood types. After, I draw another sample and ask the students to be creative in thinking of unique 'complementary' pairs of antigen and antibody as they are supposed to combine with each other.
The examples I use are:
Kanye West - Kim Kardashian
Foot - Shoe
Fire hydrant and dog
The point here is for the students to know that they are complementary to each other so they will agglutinate when they recognize each other.
Some student examples:
Donald Trump - USA flag
Justin Trudeau - Canadian flag
Kendrick Lamar - Compton (I don't really know much about this but the student had a strong sense of pop culture)