stolen from my sister's Discord:

library(ggplot2)
library(cowplot)

p1 <- ggplot() +
geom_segment(aes(x=1,y=1,xend=1,yend=3), color='navy', linewidth=3) +
xlim(0.5,3.5) +
ylim(0.5,3.5) +
theme_void()

p2 <- ggplot() +
geom_segment(aes(x=1,y=1,xend=1,yend=3), color='navy', linewidth=3) +
geom_segment(aes(x=2.5,y=1,xend=2.5,yend=2.5), color='darkorchid3', linewidth=3) +
xlim(0.5,3.5) +
ylim(0.5,3.5) +
theme_void()

p3 <- ggplot() +
geom_segment(aes(x=1,y=1,xend=1,yend=3), color='navy', linewidth=3) +
geom_segment(aes(x=2.5,y=1,xend=2.5,yend=3), color='grey', linewidth=3) +
xlim(0.5,3.5) +
ylim(0.5,3.5) +
theme_void()

p4 <- ggplot() +
geom_segment(aes(x=1,y=1,xend=1,yend=3), color='navy', linewidth=3) +
geom_segment(aes(x=1.25,y=1.5,xend=3.25,yend=1.5), color='darkorchid1', linewidth=3) +
xlim(0.5,3.5) +
ylim(0.5,3.5) +
theme_void()

plot_grid(p1,p2,p3,p4,ncol=2,nrow=2)