library(tidytext)
library(dplyr)
library(tidyr)
library(stylo)
library(ggplot2)

txt1 <- c("this is a sample document about Computer Science", "Not all sample documents are about science, they can be about art too", "and sometimes they are just useless")
names(txt1) <- c("Doc1", "Doc2", "Doc3")
df1 <- data.frame(doc = names(txt1), texts = txt1, stringsAsFactors = FALSE)



a1 <- df1 %>% unnest_tokens(output = word, input = texts) %>%
group_by(doc, word) %>%
summarise(totals = n()) %>%
ungroup %>%
spread(word, totals, fill = 0) %>%
select(-doc) %>% as.matrix %>%
scale(center = TRUE, scale = TRUE) %>%
dist.cosine %>%
cmdscale %>%
data.frame

a1$name <- 1:nrow(a1)

ggplot(data = a1, aes(x = X1, y = X2)) +
geom_text(aes(label = name))