## simulate 500 randomly scattered pts in a diamond
## with vertices at (-1,0), (0,1), (1,0), (0,-1).

z = matrix(0,ncol=2,nrow=1200)
j=1
for(i in c(1:1200)){
    x = runif(1)*2-1
    y = runif(1)*2-1
    if(abs(x)+abs(y)<1){
          z[j,] = c(x,y)
          j = j+1
          }
    }
z2 = z[1:500,]  ## but check that you have kept at least 500 pts 
plot(z2)
plot(z2[,1],z2[,2])
lines(c(-1,0,1,0,-1),c(0,1,0,-1,0))
## a little better: 
plot(c(-1,0,1,0,-1),c(0,1,0,-1,0),type="l",xlab="x",ylab="y")
points(z2)



diamond3 = function(k,n){
   z = matrix(0,ncol=2,nrow=n)
   j=1
   for(i in c(1:n)){
      x = runif(1)*2-1
      y = runif(1)*2-1
      if(abs(x)+abs(y)<1){
          z[j,] = c(x,y)
          j = j+1
          }
       }
   if(j<k) cat("Problem: kept less than k pts.")
   z[1:k,]
}

  
z = diamond3(1000,3000)
plot(c(-1,0,1,0,-1),c(0,1,0,-1,0),type="l",xlab="",ylab="")
points(z)


## MAKE TEAMS:
x = c("myley", "emilyfu", "kevinfujii", "shang", "chris", "royen",
"sam","emilykosko", "jingjing", "kwan","victor", 
"eric", "scott", "michael", "andres",
"kevinvallee", "ben",
"joseph", "steven", "jay", "ross", "nick")



n = length(x)  ## 26

runif(1)

name1 = c("a","b","c","d","e","f","g","h","i", "j","k","l","m")

teams = function(){
y = x[sample(n)]
for(i in 1:13){
cat("\n", name1[i], y[(2*i-1):(2*i)])
}
}

teams()

# a ben andres
# b sam michael
# c steven kevinvallee
# e ross kwan
# f myley chris
# g eric royen
# h emilyfu scott
# i shang jingjing
# j nick joseph
# k victor jay
# m kevinfujii emilykosko