library(tidyverse)

my_grid <- tibble(
  x = c(1:30),
  y = c(1:30)
) %>% expand.grid()

my_grid <- my_grid %>%
  mutate(x_noise = rnorm(nrow(my_grid), mean=0, sd=0.1),
         y_noise = rnorm(nrow(my_grid), mean=0, sd=0.1),
         hue  = runif(nrow(my_grid),min=0, max=2*pi),
         angle_45 = sample(seq(0,2*pi,by=pi/4),size=nrow(my_grid),replace=T),
         radius = ifelse(angle_45 %in% c(0,pi/2,pi,pi+(pi/2),2*pi),1,sqrt(2)))



my_grid %>%
  ggplot(aes(x=x,y=y)) +
  geom_point(size=10,shape=21, stroke=1, fill="#000000ae", color="#000000") +
  geom_point(aes(x,y=y), size=4, color="#ffffffde") +
  geom_spoke(aes(angle=angle_45,radius=radius),
             color="#ffffffde", size=1.5, lineend="round") +
  theme_void() +
  coord_fixed()


ggsave("grid_pattern.png", width=9, height=9, dpi=200)