library(magrittr)
library(dplyr)
library(tidyr)
library(ggplot2)
set.seed(1)
dat <- r_data_frame(12,
                    name,
                    r_series(grade, 100, relate = "+1_6")
) 

dat %>%
  gather(Time, Grade, -c(Name)) %>%
  mutate(Time = as.numeric(gsub("\\D", "", Time))) %>%
  ggplot(aes(x = Time, y = Grade, color = Name, group = Name)) +
  geom_line(size=.8) + 
  theme_bw(16) +
  ggtitle("Correlated data set")