[Jack Land]

a Mercator projection
an Erlenmeyer flask
a Potemkin village
a Lissajous figure
a Geiger counter
a Venn diagram
a Möbius strip
a Klein bottle
a lazy Susan
a Petri dish
a Pitot tube
a Leyden jar
a Pitman arm
a Venturi tube
a Pelton wheel
a Bunsen burner
a Rorschach plate
an Argand diagram
a Foucault pendulum