diff --git a/members/revsqrt/tests/features/book/revsqrt.feature b/members/revsqrt/tests/features/book/revsqrt.feature
index af08e5d..c44302e 100644
--- a/members/revsqrt/tests/features/book/revsqrt.feature
+++ b/members/revsqrt/tests/features/book/revsqrt.feature
@@ -1,6 +1,122 @@
-Feature: inverted square root feature
+Feature: inverted square root calculation
 
-  Scenario: If we calculate the inverted square root of a number using fast inverted square root, it's about the same as if we calculate it normally
+  Scenario: Calculate fast inverted sqrt
     Given a number
-    When We calculate the the inverted square root of a number using fast inverted square root
-    Then The result is about the same as if we calculate it normally
+    When we calculate the inverted square root of it using the fast inverted square root algorithm
+    Then the result is about the same as if we calculate it normally
+
+  Scenario: Calculate regular inverted sqrt
+    Given a number
+    When we calculate the inverted square root of it normally
+    Then the result can be calculated
+
+  Scenario: Can the fast inverted sqrt be calculated?
+    Given a number
+    When we calculate the inverted square root of it using the fast inverted square root algorithm
+    Then the result can be calculated
+
+  Scenario: Can the regular inverted sqrt be calculated?
+    Given a number
+    When we calculate the inverted square root of it normally
+    Then the result can be calculated
+
+  Scenario: Calculate fast inverted sqrt with specific numbers
+    Given the number n
+      | n            |
+      | 1            |
+      | 1.1          |
+      | 100          |
+      | 1337         |
+      | 123.45678900 |
+      | 1337.1337    |
+    When we calculate the inverted square root of it using the fast inverted square root algorithm
+    Then the result is about the same as m
+      | m                    |
+      | 1                    |
+      | 0.9534625892455922   |
+      | 0.1                  |
+      | 0.02734854943722097  |
+      | 0.0900000004095      |
+      | 0.027347182112297627 |
+
+  Scenario: Calculate regular inverted sqrt with specific numbers
+    Given the number n
+      | n            |
+      | 1            |
+      | 1.1          |
+      | 100          |
+      | 1337         |
+      | 123.45678900 |
+      | 1337.1337    |
+    When we calculate the inverted square root of it normally
+    Then the result is m
+      | m                    |
+      | 1                    |
+      | 0.9534625892455922   |
+      | 0.1                  |
+      | 0.02734854943722097  |
+      | 0.0900000004095      |
+      | 0.027347182112297627 |
+
+  Scenario: Some numbers are about the same (0)
+    Given the number n
+      | n            |
+      | 1            |
+      | 1.0001       |
+      | 0.999        |
+      | 0.9999999999 |
+    Then they are about the same
+
+  Scenario: Some numbers are about the same (1)
+    Given the number n
+      | n            |
+      | 10           |
+      | 10.0001      |
+      | 9.997        |
+      | 10.025       |
+    Then they are about the same
+
+  Scenario: Some numbers are about the same (-3)
+    Given the number n
+      | n            |
+      | -1000        |
+      | -1000.1      |
+      | -1001.1      |
+    Then they are about the same
+
+  Scenario: Some numbers are about the same (3)
+    Given the number n
+      | n            |
+      | -1000        |
+      | -1000.1      |
+      | -1001.1      |
+    Then they are about the same
+
+  Scenario: Some numbers are about the same (7)
+    Given the number n
+      | n               |
+      | 10000000        |
+      | 10000000        |
+      | 10000300        |
+      | 10000000.1      |
+      | 10000001.1      |
+    Then they are about the same
+
+  Scenario: Some numbers are not about the same (1)
+    Given the number n
+      | n                  |
+      | 2                  |
+      | -2                 |
+      | 0                  |
+      | 20                 |
+      | 20000              |
+    Then they are not about the same
+
+  Scenario: Some numbers are not about the same (7)
+    Given the number n
+      | n               |
+      | 10000000        |
+      | 10001000        |
+      | 0               |
+      | 20000001.1      |
+    Then they are not about the same
diff --git a/members/revsqrt/tests/revsqrt.rs b/members/revsqrt/tests/revsqrt.rs
index e14872e..2dfad6d 100644
--- a/members/revsqrt/tests/revsqrt.rs
+++ b/members/revsqrt/tests/revsqrt.rs
@@ -1,31 +1,133 @@
-use cucumber::{given, then, when, World};
+use std::iter::zip;
+
+use cucumber::{gherkin::Step, given, then, when, World};
 use rand;
 
 #[derive(Debug, Default, World)]
 pub struct NumWorld {
-    number: f32,
-    result: f32,
+    numbers: Vec<(f32, f32)>,
 }
 
 // is n about the same as m?
+// This is actually not so easy! How do you measure "about same"ness?
+// Also, it is not transitive, as 1 ≈ 1.1 ≈ 1.2 ≈ 1.3 ≈ ... ≈ 2 ≈ ... ≈ 3 ≈ ... ≈ infinity, that's
+// a thought of me at least?
+#[inline]
 fn about_same(n: f32, m: f32) -> bool {
-    (n - m) * 1000f32 < 1f32
+    dbg!((n, m));
+    dbg!((n - m).abs());
+    dbg!(calc_gate(n, m));
+    dbg!((n - m).abs() < calc_gate(n, m));
+    (n - m).abs() <= calc_gate(n, m)
 }
 
-// Steps are defined with `given`, `when` and `then` attributes.
-#[given(regex = r"^a number$")]
-async fn hungry_cat(world: &mut NumWorld) {
-    world.number = rand::random();
+#[inline]
+fn calc_gate(n: f32, m: f32) -> f32 {
+    0.01 + ((n.abs().sqrt().min(m.abs().sqrt())).abs() / 10f32)
 }
 
-#[when("We calculate the the inverted square root of a number using fast inverted square root")]
+#[given(regex = r"the number n")]
+async fn give_specific_number(world: &mut NumWorld, step: &Step) {
+    if let Some(table) = step.table.as_ref() {
+        for row in table.rows.iter().skip(1) {
+            // NOTE: skip header
+            let n = row[0].parse::<f32>().unwrap();
+            world.numbers.push((n, f32::NAN));
+        }
+    }
+}
+
+#[given("a number")]
+async fn give_rand_number(world: &mut NumWorld) {
+    world.numbers.push(rand::random());
+}
+
+#[when("we calculate the inverted square root of it using the fast inverted square root algorithm")]
 async fn calc_fast_inv_sqrt(world: &mut NumWorld) {
-    world.result = revsqrt::fast_inverse_sqrt(world.number);
+    for pair in &mut world.numbers {
+        pair.1 = revsqrt::fast_inverse_sqrt(pair.0)
+    }
 }
 
-#[then("The result is about the same as if we calculate it normally")]
+#[when("we calculate the inverted square root of it normally")]
+async fn calc_reg_inv_sqrt(world: &mut NumWorld) {
+    for pair in &mut world.numbers {
+        pair.1 = revsqrt::regular_inverse_sqrt(pair.0)
+    }
+}
+
+#[then("the result is about the same as if we calculate it normally")]
 async fn comp_result_with_normal(world: &mut NumWorld) {
-    assert!(about_same(world.number, world.result));
+    for pair in &mut world.numbers {
+        assert!(about_same(pair.1, revsqrt::regular_inverse_sqrt(pair.0)));
+    }
+}
+
+#[then("the result can be calculated")]
+async fn can_be_calculated(world: &mut NumWorld) {
+    for pair in &mut world.numbers {
+        assert!(!pair.0.is_nan());
+        assert!(!pair.1.is_nan());
+        assert!(pair.0.is_finite());
+        assert!(pair.1.is_finite());
+    }
+}
+
+#[then(regex = r"the result is m")]
+async fn result_is(world: &mut NumWorld, step: &Step) {
+    if let Some(table) = step.table.as_ref() {
+        for (row, i) in zip(table.rows.iter().skip(1), 0..table.rows.len() - 1) {
+            // NOTE: skip header
+            let m = row[0].parse::<f32>().unwrap();
+            assert_eq!(world.numbers[i].1, m);
+        }
+    }
+}
+
+#[then(regex = r"the result is about the same as m")]
+async fn result_is_about(world: &mut NumWorld, step: &Step) {
+    if let Some(table) = step.table.as_ref() {
+        for (row, i) in zip(table.rows.iter().skip(1), 0..table.rows.len() - 1) {
+            // NOTE: skip header
+            let m = row[0].parse::<f32>().unwrap();
+            assert!(
+                about_same(world.numbers[i].1, m),
+                "{} and {} are not about the same!",
+                world.numbers[i].1,
+                m
+            );
+        }
+    }
+}
+
+#[then("they are about the same")]
+async fn they_are_about_the_same(world: &mut NumWorld) {
+    let mut still_same = true;
+    let mut last_num = world.numbers[0].0;
+    for tup in &world.numbers {
+        still_same &= about_same(tup.0, last_num);
+        assert!(
+            still_same,
+            "{} and {} are not about the same! (gate: {})",
+            tup.0, last_num, calc_gate(tup.0, last_num)
+        );
+        last_num = tup.0;
+    }
+}
+
+#[then("they are not about the same")]
+async fn they_are_not_about_the_same(world: &mut NumWorld) {
+    let mut found_a_same = false;
+    let mut last_num = f32::NAN;
+    for tup in &world.numbers {
+        found_a_same |= about_same(tup.0, last_num);
+        assert!(
+            !found_a_same,
+            "{} and {} are about the same! (gate: {})",
+            tup.0, last_num, calc_gate(tup.0, last_num)
+        );
+        last_num = tup.0;
+    }
 }
 
 #[tokio::main]