You're right. It wasn't well posed. My apologies. I suspect the gaps appear because the spring constants chosen would lead to impossibilities. I'll investigate this myself and, if I'm wrong, I'll re-post.
Naughty me! I was so delighted to see the importation of the 3+4i without an asterisk that I failed to notice that the "i" is lower case. So it DIDN'T import the file as a number but as text (inside 3 lots of curly brackets). By the way, when...