using Plots
default(size = (400, 250))

A = plot(rand(10); label="A")
B = plot(rand(10); label="B")
C = plot(rand(10); label="C")
D = plot(rand(10); label="D")

plot()

plot(margin=0Plots.mm)

E = plot(framestyle=:none, margin=0Plots.mm)

F = plot(title="Plot Title", framestyle=:none, margin=0Plots.px)

G = plot(title="Plot Title", framestyle=:none, margin=0Plots.px, bottommargin=-50Plots.px)

plot(A, B, E, C; size=(600, 375), layout=(2, 2))

plot(F, A, B, C, D; size=(600, 400), layout=@layout[f{0.1h}; [a b; c d]])

plot(G, A, B, C, D; size=(600, 400), layout=@layout[f{0.05h}; [a b; c d]])